Seatbelt Locking Tongue Guide Piece to Prevent Webbing Fraying

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Solution Overview

Problem

The webbing of a seatbelt device can become frayed due to friction when pulled in an oblique direction relative to the locking tongue, leading to an unsightly mottled appearance.

Innovation Solution

A locking tongue design featuring a guide piece and locking component that restricts the webbing's position within the tongue body, preventing friction and maintaining the webbing's surface integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the webbing is pulled in an oblique direction relative to the locking tongue body, then the locking tongue can be attached and detached from the buckle, but the webbing slides over the locking component and becomes skewed, causing friction and fraying of the webbing fibers

Engineering Contradiction:
Improveattachment and detachment of locking tongueVSAvoidfriction causing webbing fraying
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A guide piece is introduced as an intermediary component between the webbing and the locking component. This guide piece has a guide surface that directs the webbing along a predetermined path, preventing the webbing from contacting the locking component in an oblique direction. The guide piece mediates the interaction between the webbing and locking mechanism, ensuring smooth operation without friction-induced damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the webbing is constrained to move through a predetermined path, then the webbing surface remains smooth and aesthetically pleasing, but the locking mechanism structure becomes more complex with the addition of a guide piece

Engineering Contradiction:
Improvewebbing surface integrityVSAvoidlocking mechanism structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The locking tongue is segmented into distinct functional components: the tongue body, the locking component, and the guide piece. Each component has a specific function - the guide piece handles webbing guidance, the locking component handles locking/unlocking, and the tongue body provides structural support. This segmentation allows each component to be optimized for its specific function while maintaining overall system simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide piece is positioned within the tongue body and works in conjunction with the locking component. The guide piece's guide surface is nested within the overall locking mechanism structure, allowing the webbing to follow a predetermined path through the tongue body without adding significant external complexity to the device.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4606657A1Locking tongue
Publication Date: 2025.08.27 AUTOLIV DEV AB
  • EP4606657A1 patent drawingFigure 1~2
  • EP4606657A1 patent drawingFigure 3A~4
  • EP4606657A1 patent drawingFigure 5A~5B

AI summary

The locking tongue of the present invention includes: a tongue body having a first insertion hole and a second insertion hole for inserting a webbing, and a tongue plate for detachably connecting to a buckle; a locking component that is supported so as to be displaceable between a release position, which allows movement of the webbing away from the first insertion hole, and a lock position, which prevents movement of the webbing approaching the first insertion hole; and a guide piece attached to the locking component that restricts a position through which the webbing passes relative to the locking component. In accordance with the locking tongue having such a configuration, the guide piece regulates the position through which the webbing passes, thereby making it possible to avoid contact between the webbing and the inner wall of the tongue body.