Expanding Electrical Contact for Stable Connector Pressure

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Solution Overview

Problem

Existing electrical contacts experience undesirable effects such as energy loss, localized heating, thermal expansion, and inconsistent mechanical engagement due to small conduction areas and varying contact forces, leading to increased resistance and potential arcing.

Innovation Solution

Incorporating an intermediate element with higher electrical resistivity and thermal expansion than the inner and outer conductors, which is bonded or inserted between them, to provide consistent contact force and self-tightening mechanism, reducing resistance and enhancing conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If direct contact between inner conductor and outer conductor is used, then electrical conductivity is improved, but localized heating and resistance increase due to small conduction area

Engineering Contradiction:

Improveenergy lossVSAvoidconduction area

Core Design Contradiction:

Loss of energyVSArea of stationary object

Solution Approach 1:

An intermediate element with higher thermal expansion coefficient than both the inner conductor and outer conductor is inserted between them. This intermediary element expands more upon heating, maintaining consistent contact pressure at the contact interfaces, thereby preventing localized heating and resistance increase while ensuring adequate conduction area.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The intermediate element is specifically selected or designed to have a thermal expansion coefficient higher than both the inner conductor and outer conductor. When temperature increases, the intermediate element expands more, generating compensating contact pressure that offsets thermal expansion gaps, thus maintaining stable electrical conductivity and preventing energy loss.

Inventive Principle:

Principle #37Thermal expansion

2Reliability

If contact force is increased to improve electrical conductivity, then resistance decreases, but mechanical engagement consistency deteriorates due to varying contact forces

Engineering Contradiction:

Improveconnection stabilityVSAvoidcontact force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The intermediate element's higher thermal expansion coefficient enables it to automatically adjust contact forces in response to temperature changes. As temperature rises, the intermediate element expands more, maintaining consistent contact pressure at both interfaces, thereby ensuring reliable electrical connection without excessive or varying contact forces.

Inventive Principle:

Principle #37Thermal expansion

3Stability of the object's composition

If intermediate element with higher thermal expansion is added, then contact pressure consistency is improved, but device complexity increases

Engineering Contradiction:

Improvecontact pressure consistencyVSAvoidstructure complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

A simple intermediate element with specific material properties (higher thermal expansion coefficient) is inserted between the inner conductor and outer conductor. This single-component solution maintains contact pressure consistency through its thermal expansion characteristics without requiring complex mechanisms or multiple components, thus improving stability while minimizing added complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Volume of stationary object

If small conduction area is used, then connector size is reduced, but localized heating and arcing increase

Engineering Contradiction:

Improveconnector sizeVSAvoidlocalized heating

Core Design Contradiction:

Volume of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The intermediate element with higher thermal expansion coefficient compensates for thermal expansion effects during current flow. As temperature increases, the intermediate element expands more, maintaining consistent contact pressure that prevents localized heating and arcing, thereby allowing safe operation at smaller connector sizes without the harmful effects of reduced conduction area.

Inventive Principle:

Principle #37Thermal expansion

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 intermediate element maintains consistent contact pressure, lowers resistance, and prevents localized heating, improving electrical conductivity and connection stability across varying temperatures and currents.

Implementation Method 1

The material of the intermediate element has one or both of a higher electrical resistivity and a higher rate of thermal expansion than the material of both the inner conductor and the outer conductor

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The actual areas of conduction may be small, causing undesirable effects like energy loss, localized heating, higher temperatures

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS20250286297A1Connector with expanding contact

Publication Date: 2025.09.11 HARTING INT INNOVATION AG

AI summary

An electrical contact having an inner conductor, an outer conductor and an intermediate element located between the inner conductor and the outer conductor. The material of the intermediate element has one or both of a higher electrical resistivity and a higher rate of thermal expansion than the material of both the inner conductor and the outer conductor. Methods of forming an electrical contact, and an electrical connector including an electrical contact are also disclosed.