Electrical Contact Pre-Coating Strip for Small Diameter Tubes

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Solution Overview

Problem

Existing methods for manufacturing electrical contacts, such as Flex-pin and Twist-pin technologies, face challenges in producing contacts with small diameters, as they struggle to apply surface coatings inside the tubes, limiting their physico-chemical performance and increasing production costs.

Innovation Solution

A method involving pre-coating a strip with a surface coating, such as nickel and gold, before cutting and forming it into a tube, allowing for the production of contacts with small diameters and high physico-chemical performance, and integrating the contact terminal with the tube for enhanced mechanical and electrical reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If surface coating is applied to the inner surface of small-diameter tubes by electrolysis, then the physico-chemical performance is improved, but the manufacturing cost increases and the process becomes impossible for very small diameters

Engineering Contradiction:
Improvephysico-chemical performanceVSAvoidmanufacturing cost and feasibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies surface coating to the strip before forming it into a tube, rather than coating the finished tube. This preliminary coating action allows the coating process to occur on a flat, accessible surface where electrolysis can effectively reach all areas, including what will become the inner surface of the tube after forming. This resolves the technical contradiction by making the coating process feasible for small-diameter tubes without increasing complexity or cost.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent inverts the conventional sequence by coating the strip before forming rather than coating the formed tube. This inversion transforms an impossible or difficult process (coating small-diameter tube interiors) into a simple, effective process (coating a flat strip surface), thereby improving reliability while maintaining ease of manufacture.

Inventive Principle:
Principle #13The other way round (Inversion)

2Volume of moving object

If the internal diameter of the tube is reduced to achieve compact connectors, then the connector size is reduced, but the surface coating application becomes impossible

Engineering Contradiction:
Improveconnector sizeVSAvoidsurface coating application
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The surface coating is applied to the strip before it is formed into a tube of small diameter. This preliminary action ensures that the coating is already present on the material that will become the tube, eliminating the need to apply coating to the finished small-diameter tube where the process would be impossible.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the dimensionality of the coating surface from a three-dimensional curved inner surface of a small tube (difficult to access) to a two-dimensional flat surface of the strip (easy to access). This dimensional transformation allows electrolytic coating to be applied effectively before the tube is formed, enabling compact connector design without sacrificing coating quality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If precious metals are used for the contact terminal to ensure high performance, then the connection reliability is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a composite structure where a copper or copper-alloy strip provides the mechanical strength and form, while a layer of precious metal (such as gold or silver) applied by electrolysis provides the electrical conductivity and connection reliability. This composite approach achieves high connection reliability while keeping costs lower than using solid precious metal, as the precious metal is used only as a thin surface layer.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies precious metal coating only to the surfaces that require high electrical conductivity and corrosion resistance, rather than using solid precious metal throughout. The electrolytic coating process deposits precious metal layers specifically on the strip surfaces that will become contact surfaces, providing local quality enhancement where needed while maintaining cost-effectiveness.

Inventive Principle:
Principle #3Local quality

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

This approach enables the cost-effective manufacture of electrical contacts with high physico-chemical performance, suitable for harsh environments, by ensuring consistent and controlled coating thickness, and automating the assembly process, reducing handling and production costs.

Implementation Method 1

After shaping the contact, it is covered by a surface coating (generally an underlayer of nickel followed by a layer of gold) by electrolysis.

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

a tube is produced by rolling the edge of the strip

Methodology Applied
Scientific EffectPlastic deformation: Deformation

Data Source

PatentEP3109948B1Method for manufacturing an electrical contact, and electrical contact
Publication Date: 2019.03.06 AXONCABLE
  • EP3109948B1 patent drawingFigure 1~2

AI summary

A method for manufacturing an electrical contact (100) in which: b) a tube (30) is formed by creating the edge of a strip; e) without detaching the tube (30) from the strip (12), a first conductive element (20) is fixed in a first end (31) of the tube, such that a portion of the tube remains empty on the side of its second end (37). An electrical contact comprising a tube (30) and a contact terminal (20) one end of which is fixed in a first end (31) of the tube (30); and in which an inner surface (32) of the tube is covered by a surface coating (16, 18) called the inner coating, and the thickness of the inner coating, or of at least one layer of the inner coating, is at least 1 µm, or even 1.27 µm.