Seatback Airbag Tether Layout for Cover-Cutting Deployment

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Solution Overview

Problem

Existing airbag devices face issues with tethers that fail to properly cut through seat coverings, leading to abnormal deployment of the airbag cushion, which compromises passenger safety.

Innovation Solution

The airbag device incorporates a tether positioned between a foam pad and a covering, which unfolds by cutting through the covering during deployment, with features like slits and position regulation grooves to facilitate smooth deployment without high force requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the tether is positioned to cut through the covering during deployment, then the airbag cushion can be deployed, but the tether may fail to properly cut the covering leading to abnormal deployment

Engineering Contradiction:
Improvetether deployment reliabilityVSAvoidtether positioning complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-positioning the tether between the foam pad and the covering in a folded state before deployment. The tether is预先 placed in a specific location (between the foam pad and covering) with a predetermined folding structure, so that during deployment it automatically unfolds and cuts the covering without requiring additional positioning mechanisms. This resolves the contradiction by ensuring reliable cutting action while avoiding complex positioning systems.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The tether is divided into multiple segments or folds along its length, creating a segmented structure that allows it to be compactly stored and then progressively unfold during deployment. This segmentation enables the tether to achieve the necessary length and positioning for cutting the covering without requiring a single long, complex positioning mechanism, thus improving reliability while reducing overall device complexity.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the tether is folded at the lateral side of the foam pad, then it can be compactly stored, but it may require high force to unfold and cut the covering

Engineering Contradiction:
Improvetether storage compactnessVSAvoidforce required for tether deployment
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The foam pad serves as an intermediary element between the tether and the covering. The tether is positioned between the foam pad and the covering, using the foam pad as a mediator to guide and support the tether during deployment. This intermediary arrangement allows the tether to unfold along a predetermined path with reduced friction and resistance, decreasing the force required while maintaining compact storage capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical parameters of the deployment process by introducing a slit in the foam pad where the tether passes through. This parameter change (creating an opening) reduces the resistance and force required for the tether to unfold and cut the covering, while the tether remains compactly folded during storage. The slit acts as a controlled pathway that modifies the deployment parameters favorably.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the tether unfolds while cutting through the covering, then normal deployment is achieved, but the lateral chamber and front chamber may excessively separate

Engineering Contradiction:
Improveairbag deployment normalityVSAvoidairbag chamber configuration stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The tether serves multiple functions simultaneously: it acts as a cutting tool to penetrate the covering, a positioning element to maintain proper spatial relationships, and a restraining mechanism to prevent excessive separation of chambers. This multi-functionality allows the same component to ensure normal deployment while maintaining chamber configuration stability, resolving the contradiction between deployment reliability and configuration stability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The tether is strategically positioned at specific locations (between the foam pad and covering, connected to the airbag cushion) to perform localized functions. By concentrating its restraining and positioning effects at critical points, the tether prevents excessive separation of the lateral and front chambers while still allowing necessary deployment movement. This localized quality approach maintains chamber configuration stability without compromising deployment normality.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4438417B1Airbag device
Publication Date: 2025.10.15 HYUNDAI MOBIS CO LTD
  • EP4438417B1 patent drawingFigure 1
  • EP4438417B1 patent drawingFigure 2
  • EP4438417B1 patent drawingFigure 3

AI summary

An airbag device includes a tether (300) having an improved folding position that enables the tether (300) to unfold as it cuts through a covering (400). The airbag device may include a foam pad (100) embedded in a seatback (10), an airbag cushion (200) folded at a lateral side of the foam pad and configured to be deployed forward, a covering (400) shaped to cover the foam pad and configured to cover the seatback, and a tether positioned between the foam pad and the covering and connected between the seatback and the airbag cushion. The tether is configured to unfold as it cuts through the covering when the airbag cushion is deployed.