Thigh Airbag Tethers Prevent Pelvic Submarining

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Solution Overview

Problem

Existing vehicle seat airbag systems fail to effectively prevent submarining, where the occupant slides beneath the seat belt during emergencies, due to limitations in comfort and effectiveness of current anti-submarining bars and under-thigh airbags that may rock or roll, reducing their effectiveness.

Innovation Solution

A vehicle seat airbag system with a thigh airbag connected to the seat frame and tethers that restrict forward movement, inflating to raise the seat base cushion and force the pelvis into frictional contact with the lap belt, thereby preventing submarining, and utilizing a tether tensioning device to enhance support during inflation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an under thigh airbag is added on the seat base to decrease the gap between the lap belt and the seat base, then the effectiveness in preventing submarining is improved, but the airbag may rock or roll forward under friction from the occupant during acceleration, which increases the gap and reduces effectiveness

Engineering Contradiction:

Improveanti-submarining effectivenessVSAvoidairbag position stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses a flexible airbag made of thin film material that can deform and conform to the seat base cushion surface. The airbag includes a low-point midsection that allows it to flex and adapt to the curved surface of the seat base, preventing rolling while maintaining contact. This flexible thin film structure resolves the contradiction by allowing the airbag to be effective in preventing submarining without rocking or rolling forward during acceleration.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces a new dimensional feature by creating a low-point midsection in the airbag structure, which adds a vertical dimension variation to the airbag's contact surface. This dimensional change allows the airbag to conform to the curved seat base cushion surface, distributing forces more effectively and preventing forward rolling while maintaining anti-submarining effectiveness.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If anti-submarining bars or brackets are used to limit occupant submarining motion, then the effectiveness in preventing submarining is improved, but the occupant comfort is impaired

Engineering Contradiction:

Improveanti-submarining effectivenessVSAvoidoccupant comfort

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces rigid anti-submarining bars with a pneumatic airbag system. The airbag can be inflated to provide the necessary support force to prevent submarining, and deflated when not needed, providing a soft, comfortable interface with the occupant's thighs. This pneumatic approach resolves the contradiction by maintaining anti-submarining effectiveness while eliminating the comfort impairment caused by rigid bars.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the physical state parameter of the support structure from rigid (bars) to flexible inflatable (airbag). By controlling the inflation pressure and volume of the airbag, the system can adapt its support characteristics to provide both effective anti-submarining protection and comfortable occupant support, resolving the contradiction between effectiveness and comfort.

Inventive Principle:

Principle #35Parameter changes

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

The system effectively mitigates submarining by maintaining the pelvis in frictional contact with the lap belt, reducing pelvis rotation and forward excursion, and providing improved comfort compared to traditional anti-submarining methods.

Implementation Method 1

at least one airbag tether is connected to the seat frame and to the thigh airbag. During inflation of the thigh airbag, the at least one airbag tether restricts a forward movement of the thigh airbag

Methodology Applied

Scientific EffectTension: Tension

Implementation Method 2

When inflated, the thigh airbag pushing upward on the seat base cushion forces the pelvis of the occupant upward

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 3

forces the pelvis of the occupant upward into frictional contact with the lap belt, thereby mitigating against submarining of the pelvis beneath the lap belt

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS11554740B1Anti-submarining thigh air bag with tethers

Publication Date: 2023.01.17 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An automobile vehicle airbag system includes a vehicle seat having a seat back rotatably connected to a seat base, with the seat base mounted on a seat frame. A seat base cushion is mounted on the seat frame upon which an occupant is seated. A thigh airbag is connected to the seat frame and positioned above the seat frame and below the seat base cushion in a thigh airbag uninflated condition. At least one airbag tether is connected to the seat frame and to the thigh airbag. A lap belt is connected to the vehicle seat and contacts a pelvis of the occupant. When inflated the thigh airbag pushes upward on the seat base cushion forcing the thighs and pelvis of the occupant upward into frictional contact with the lap belt, thereby mitigating against submarining of the pelvis beneath the lap belt.