Non-Destructive Thermocouple Contact Testing Before Harness Assembly

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Solution Overview

Problem

Existing methods for testing thermocouple connector contacts are destructive and time-consuming, often requiring disassembly and replacement, and do not guarantee the integrity of the replacement contacts, leading to inefficiencies in the manufacturing process.

Innovation Solution

A non-destructive testing system using alligator clips to connect known and unknown thermocouple contacts, measuring the Seebeck voltage with a data acquisition card to determine contact integrity without assembly, utilizing a heat source to induce a temperature differential and analyze the resulting voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If destructive testing methods are used to test thermocouple connector contacts, then defects can be detected, but the contacts are damaged and must be replaced, increasing time and complexity

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidtesting and replacement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces mechanical/destructive testing methods with an electrical measurement system. A testing device applies a known voltage to the thermocouple contact and measures the resulting current to detect defects, eliminating the need for physical destruction or disassembly of the connector assembly.

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

Solution Approach 2:

The patent creates an electrical model or equivalent circuit representation of the thermocouple contact to test its properties without physically altering the actual contact. By measuring electrical parameters (voltage, current, resistance) in this equivalent system, defects can be identified while the original contact remains intact for installation.

Inventive Principle:
Principle #26Copying

2Reliability

If full assembly and testing of electrical wiring harnesses is performed, then contact quality can be verified, but assembly time and manufacturing complexity increase significantly

Engineering Contradiction:
Improvecontact quality assuranceVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent performs contact quality testing before the contacts are installed into the connector assembly. By testing individual contacts in advance using the electrical measurement device, defects are identified early in the manufacturing process, preventing the need for time-consuming disassembly and rework of fully assembled connectors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent divides the testing process into separate, independent steps: first testing individual contacts using the electrical measurement device, then assembling only the verified good contacts into the connector. This segmentation allows parallel processing and eliminates the need to test entire assembled connectors, significantly improving manufacturing throughput.

Inventive Principle:
Principle #1Segmentation

3Productivity

If replacement contacts are installed without prior testing, then assembly speed increases, but defect escapes occur and rework is required

Engineering Contradiction:
Improveassembly speedVSAvoidcontact integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements preliminary testing of contacts before they are assembled into the final connector product. The electrical measurement device quickly verifies contact quality in advance, allowing assembly personnel to confidently install only verified good contacts without slowing down the assembly process or risking defect escapes.

Inventive Principle:
Principle #10Preliminary action

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

Enables quick and non-destructive identification of good or bad contacts, reducing assembly time and ensuring the quality of thermocouple connectors by avoiding the need for full assembly and testing of electrical wiring harnesses.

Implementation Method 1

A thermocouple produces a temperature-dependent voltage as a result of the Seebeck effect. The Seebeck effect generates a voltage potential as a function of differential temperature between the junction and voltage measurement location.

Methodology Applied
Scientific EffectSeebeck effect: Seebeck Effect

Data Source

PatentEP4650735A1Non-destructive thermocouple contact testing tool and method
Publication Date: 2025.11.19 RTX CORP
  • EP4650735A1 patent drawingFigure 1~2
  • EP4650735A1 patent drawingFigure 3~4
  • EP4650735A1 patent drawingFigure 5

AI summary

An apparatus for testing a thermocouple contact comprises a first nondestructive connector removably connected to a known contact (202) of a thermocouple contact assembly and a second nondestructive connector removably connected to an unknown contact (204) of the thermocouple assembly. A processing device (210) is electrically connected to the first nondestructive connector and the second nondestructive connector. Responsive to connection of the thermocouple contact assembly between the first nondestructive connector and the second nondestructive connector and application of a heat source (212) to the thermocouple contact assembly a Seebeck voltage (VSB) is measured by the processing device (210).