Electrical Connector Locking Plate to Prevent Terminal Back Slip

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Solution Overview

Problem

Existing electrical connectors face issues with back slip of connection terminals due to insufficient locking force, leading to potential escape and water infiltration, especially when reduced in size for automotive applications.

Innovation Solution

A locking mechanism using a movable locking plate portion within the housing, operated by an insertable operating member from the front, ensures secure locking and prevents rearward escape of connection terminals while maintaining waterproof integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a case lance alone is used for locking, then the housing and case lances can be reduced in size, but the locking force becomes insufficient

Engineering Contradiction:
Improvehousing sizeVSAvoidlocking force
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The patent combines the case lace locking mechanism with a plate-like locking piece that extends from the terminal holder. The locking piece has a locking protrusion that engages with a locking groove in the housing, creating a combined locking system that provides sufficient locking force while maintaining compact housing dimensions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking piece is designed to be movable relative to the terminal holder, allowing it to engage and disengage from the locking groove. This dynamic mechanism enables reliable locking during assembly and provides a positive lock that prevents terminal withdrawal, while the overall housing remains compact.

Inventive Principle:
Principle #15Dynamics

2Force

If a side holder is inserted from the side of the housing to lock the connection terminal, then the locking force is improved, but water infiltration into the housing is likely to occur through the insertion hole

Engineering Contradiction:
Improvelocking forceVSAvoidwater infiltration
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

Instead of inserting the locking mechanism from the side of the housing, the patent inserts the terminal holder from the rear of the housing. The locking piece is integrated with the terminal holder and engages with the locking groove from the rear, eliminating the need for side insertion holes and preventing water infiltration pathways.

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

Solution Approach 2:

The locking function is extracted from a separate side-inserted holder and integrated into the terminal holder itself. The locking piece is formed as part of the terminal holder assembly, which is inserted from the rear, separating the locking mechanism from the side insertion approach that creates waterproofing issues.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a side holder is used for locking, then the connection terminal can be locked reliably, but the side holder may escape from the housing due to unexpected contact with another member

Engineering Contradiction:
Improvelocking reliabilityVSAvoidside holder stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The insertion direction is inverted from side insertion to rear insertion. The terminal holder with the integrated locking piece is inserted from the rear of the housing, where it is protected from external contacts. This positioning prevents the locking mechanism from being accidentally dislodged by external objects while maintaining reliable locking of the connection terminal.

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

Data Source

PatentEP3982489B1Electrical connector and method for locking connection terminal in said electrical connector
Publication Date: 2025.09.17 DELTA PLUS CO LTD
  • EP3982489B1 patent drawingFigure 1~2
  • EP3982489B1 patent drawingFigure 3
  • EP3982489B1 patent drawingFigure 4

AI summary

A locking plate portion 3 is disposed so as to be movable in a lateral direction indicated by an arrow. As in (a), a connection terminal T is inserted while a locking piece Tc of a connection portion Ta of the connection terminal T passes through an insertion groove 3d of the locking plate portion 3. Subsequently, an operating member 4 is pushed in an arrow direction with respect to the locking plate portion 3 and the locking plate portion 3 is laterally moved by a wedge mechanism. Then, as in (b), the locking piece Tc is transferred to a locking portion 3e provided in the front end side portion of the insertion groove 3d. As a result, the locking portion 3e locks the rear portion of the locking piece Tc and a rearward movement of the connection terminal T is regulated.