Connector Assembly Lock Geometry for Unseated Terminal Detection

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Solution Overview

Problem

Conventional connectors, particularly miniature coaxial connectors, lack reliable mechanisms to detect unseated or partially seated terminals due to short stroke lengths of independent secondary locks, which limits feedback to assembly operators.

Innovation Solution

An electrical connector assembly with a flexible primary terminal lock arm and an independent secondary lock (ISL) that includes a tab and window arrangement, where the tab is received within the window only when the primary lock arm is unflexed, preventing the ISL from shifting to the staged position if the terminal is not fully seated, thereby providing tactile and visual feedback for proper seating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the ISL stroke length is shortened to accommodate miniature connector size, then the connector size is reduced, but the ability to detect unseated terminals is compromised

Engineering Contradiction:
Improveconnector sizeVSAvoidunseated terminal detection
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent introduces a tab-extending-from-lock-arm as an intermediary element that bridges the gap between the shortened ISL stroke and the detection function. This tab acts as a mediator that translates the lock arm's flexed/unflexed state into a detectable position change for the ISL, enabling reliable detection even with limited stroke length

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent adds a new spatial dimension to the detection mechanism by extending a tab from the lock arm in a direction perpendicular to the ISL movement path. This creates a two-dimensional detection interface (tab position relative to ISL window) that provides detection capability without requiring increased stroke length in the primary movement dimension

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

2Volume of moving object

If the ISL stroke length is shortened, then the connector becomes more compact, but the feedback to assembly operators becomes unreliable

Engineering Contradiction:
Improveconnector sizeVSAvoidassembly feedback
Core Design Contradiction:
Volume of moving objectVSLoss of information

Solution Approach 1:

The patent enhances feedback reliability by creating a mechanical feedback system where the ISL's ability to reach its staged position provides clear tactile and visual information to assembly operators. The tab-ISL interaction creates a binary feedback state (ISL reaches staged position = terminal seated; ISL cannot reach staged position = terminal unseated) that is reliable even with short stroke length

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The tab extending from the lock arm serves as an intermediary that translates the terminal seating state into a positional signal that the ISL can detect. This intermediary element ensures that assembly feedback is not lost despite the shortened stroke length, as the tab's position relative to the ISL window provides unambiguous information about terminal seating status

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the primary terminal lock arm is allowed to flex during terminal insertion, then the terminal can be inserted, but the ISL cannot detect unseated terminals with short stroke length

Engineering Contradiction:
Improveterminal insertionVSAvoidunseated terminal detection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent segments the detection function into two independent parts: the primary lock arm's flexing capability (which enables insertion) and the ISL's detection capability (which detects seating status). The tab extending from the lock arm acts as a coupling element that links these segmented functions, allowing the ISL to detect unseated terminals even while the lock arm flexes during insertion

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tab extending from the lock arm serves as an intermediary that decouples the flexing motion from the detection mechanism. During insertion, the lock arm flexes as needed, but the tab's position relative to the ISL window changes in a predictable way that allows detection. This intermediary element enables both easy insertion and reliable detection to coexist

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4228100B1Connector assembly with an unseated terminal detection feature
Publication Date: 2026.01.21 APTIV TECHNOLOGIES AG
  • EP4228100B1 patent drawingFigure 1~2
  • EP4228100B1 patent drawingFigure 3
  • EP4228100B1 patent drawingFigure 4A~5

AI summary

An electrical connector assembly (100) includes a connector body (106) defining a terminal cavity (108) in which an electrical terminal (104) is received which has a flexible primary terminal lock arm (110) configured to secure the terminal (104) within the cavity (108) and which has a tab (116) extending from a free end of the primary terminal lock arm (110). The assembly (100) further includes an independent secondary lock (ISL) (112) defining a window therein (118), attached to the connector body (106), and movable form a pre-staged position (120) to a staged position (122). The tab (116) of the primary terminal lock arm (110) is received within the window (118) when the primary terminal lock arm (110) is in an unflexed condition when the ISL (112) is in the staged position (122). The tab (116) and window (118) cooperate to inhibit flexing of the primary terminal lock arm (110) when the ISL (112) is in the staged position (122). Alternatively, the primary terminal lock arm (210, 310) may define the window (218, 318) and the ISL (212, 312) may define the tab (216, 316).