Air Bag Vent Actuation via Tear Stitching Guide Member

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Solution Overview

Problem

Existing vehicle air bag systems face challenges in controlling inflation and deployment based on occupant position, leading to inefficient protection during impacts, as the venting mechanism may actuate prematurely or fail to actuate when the occupant is not in a normal seated position.

Innovation Solution

The air bag system incorporates a tether and guide member with releasable tear stitching that prevents the vent from actuating until the air bag reaches a predetermined pressure and deployment stage, ensuring the vent is properly oriented and actuated only when the occupant is in a normal seated position, using a resilient stop to control tension and maintain the vent in a non-actuated state until necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the vent is directly connected to the air bag without a tether and guide member mechanism, then the venting mechanism can respond quickly to inflation, but the vent may actuate prematurely or fail to actuate when the occupant is not in a normal seated position

Engineering Contradiction:

Improvevent actuation reliabilityVSAvoidtether and guide member mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The guide member is pre-configured with releasable connections (tear stitching) that are designed to fail at a specific point during air bag deployment. This preliminary arrangement ensures that the vent will only actuate when the air bag reaches a predetermined deployment stage, preventing both premature and delayed actuation regardless of occupant position

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The tether acts as an intermediary element between the air bag and the vent mechanism. It transmits the deployment force from the air bag to the vent through the guide member, providing a controlled mechanical linkage that ensures reliable vent actuation only when the air bag achieves sufficient inflation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If the tether is directly tensioned during initial deployment, then the vent can actuate immediately, but this causes premature venting before the air bag is fully pressurized

Engineering Contradiction:

Improvevent actuation speedVSAvoidcontrolled venting reliability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The releasable connection mechanism in the guide member provides a controlled delay mechanism that cushions the premature tensioning of the tether. The tear stitching holds the guide member sections together during initial inflation, allowing the air bag to build pressure before the vent actuates

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

This solution ensures reliable and controlled venting of the air bag, preventing premature inflation and ensuring adequate protection by actuating the vent only when the air bag is fully pressurized and the occupant is in a suitable position, enhancing the reliability and effectiveness of the air bag deployment.

Implementation Method 1

A resilient stop is provided on the first end of the tether for providing slack in the first end of the tether

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The first and second portions remain connected together in response to initial deployment of the protection device below a predetermined degree to prevent the tether from tensioning

Methodology Applied

Scientific EffectFracture Mechanics: Fracture Mechanics

Data Source

PatentUS9199602B1Passive air bag with slack creator

Publication Date: 2015.12.01 TRW VEHICLE SAFETY SYST INC

AI summary

An apparatus for helping to protect an occupant of a vehicle includes an inflatable vehicle occupant protection device inflatable between a vehicle surface and the vehicle occupant. The protection device includes a front panel having a portion presented toward the occupant when the protection device is in an inflated condition. A vent includes at least one opening for releasing inflation fluid from the protection device and has an actuated condition and a non-actuated condition. A tether has a first end connected to the vent for actuating the vent and a second end connected to the protection device. A guide member connected to the front panel slidably receives a portion of the tether between the first and second ends. First and second portions of the guide member are releasably connected together to define a slackened portion. The first and second portions remain connected together in response to initial deployment of the protection device below a predetermined degree to prevent the tether from tensioning such that the vent is in the non-actuated condition. Further deployment of the protection device to the predetermined degree releases the connection between the first and second portions to allow the tether to tension and act on the vent to place the vent in the actuated condition based on the position of the occupant in the vehicle.