Staggered Spring Holder Assembly for Stable Transfer Switch Contact Pressure

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Solution Overview

Problem

The existing dual-power transfer switch with bidirectional contacts faces challenges due to large occupied space and unstable contact pressure, especially when contact surfaces wear down, affecting mechanical and electrical properties, and requires multiple movable contacts with independent pressure mechanisms for stable performance.

Innovation Solution

A movable contact assembly with staggered spring holders and parallel-connected springs, which reduces installation space and ensures consistent contact pressure across multiple contacts, improving rated current capacity and short-time current withstand performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two independent elastic devices are used for each contact, then contact pressure stability is improved, but occupied space increases

Engineering Contradiction:
Improvecontact pressure stabilityVSAvoidoccupied space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines two independent elastic devices into a single integrated elastic device with two separate elastic elements. This merging approach maintains the independent contact pressure control for each contact while reducing the overall occupied space compared to using two completely separate elastic devices.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single elastic device serves multiple functions by providing independent elastic support for both the first contact and the second contact. The device universally handles contact pressure maintenance for bidirectional contacts while occupying less space than multiple separate devices would require.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Power

If multiple movable contacts are installed side by side, then rated current capacity is improved, but contact pressure consistency deteriorates

Engineering Contradiction:
Improverated current capacityVSAvoidcontact pressure consistency
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The elastic device is segmented into multiple independent elastic elements, with each element responsible for maintaining contact pressure on a specific contact. This segmentation ensures that each contact receives consistent and independent pressure control, even when multiple contacts are installed side by side to increase rated current capacity.

Inventive Principle:
Principle #1Segmentation

3Reliability

If contact surfaces become thinner due to ablation, then mechanical properties deteriorate, but contact pressure stability should be maintained

Engineering Contradiction:
Improvecontact pressure stabilityVSAvoidmechanical properties
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The elastic device provides dynamic contact pressure maintenance that automatically compensates for contact surface thinning due to ablation. As contacts wear and become thinner, the elastic elements continuously adjust to maintain stable contact pressure, ensuring reliable electrical connection even when mechanical properties of the contact surfaces deteriorate.

Inventive Principle:
Principle #15Dynamics

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 achieves compact installation, consistent contact pressure, and enhanced performance by utilizing parallel springs to provide combined force, effectively addressing the issues of space and stability in dual-power transfer switches.

Implementation Method 1

at least a pair of springs... the movable contact is held between the two spring holders and between the two springs

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3993002B1Movable contact pressure maintaining structure, movable contact assembly and dual-power transfer switch
Publication Date: 2024.07.03 SCHNEIDER ELECTRIC IND SAS
  • EP3993002B1 patent drawingFigure 1
  • EP3993002B1 patent drawingFigure 2
  • EP3993002B1 patent drawingFigure 3

AI summary

A movable contact pressure maintaining structure, acting on a movable contact of a dual-power transfer switch, wherein the movable contact pressure maintaining structure includes at least a pair of spring holders and at least a pair of springs; two corresponding spring holders in the at least a pair of spring holders are staggered and installed together relative to each other; the two spring holders are arranged such that two springs of the at least a pair of springs are respectively installed between the two spring holders in parallel; the movable contact is held between the two spring holders and between the two springs. A movable contact assembly including the movable contact pressure maintaining structure as described above. A dual-power transfer switch including the movable contact pressure maintaining structure as described above.