Lap Pretensioner Sealing Structure for Gas Emission Containment

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Solution Overview

Problem

Conventional lap pretensioners allow gas emissions from micro gas generators, posing safety risks to occupants, and parts can break or dislodge during abnormal conditions, leading to secondary accidents.

Innovation Solution

A lap pretensioner structure with a pressure unit that includes a connecting unit, a case part, a moving part, and an actuation part, which controls fluid movement within a variable space to prevent gas leaks and part dislodgment, featuring a telescopic hollow tube and an exhaust unit to direct emissions away from occupants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a micro gas generator is used to generate fluid pressure to move the anchor or buckle, then the webbing can be pulled effectively to prevent occupant movement, but gas emissions from the MGG can escape through connection paths and cable seals causing safety issues

Engineering Contradiction:

Improveoccupant safetyVSAvoidgas emissions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The connection path is divided into multiple sealed segments. The cable seal is divided into first and second seals creating separate sealed spaces. The connection unit includes a first connection unit and second connection unit with separate sealing arrangements, preventing gas from penetrating through the entire path to the exterior.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A piston is introduced as an intermediary component between the MGG and the external environment. The piston moves within the sealed connection unit, transmitting the fluid pressure force to pull the anchor or buckle while the sealed environment prevents gas emissions from reaching the exterior.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If conventional cable seals are used with gaps or inner spaces, then the structure is simpler, but gas can leak through these gaps causing burns to occupants

Engineering Contradiction:

Improveseal structureVSAvoidoccupant exposure to gas

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The harmful factor (gas emissions) is extracted and contained within a sealed environment. The sealed connection unit creates an isolated space that prevents the extraction of gas from the MGG system to the exterior environment, eliminating the harmful effect while maintaining the sealing structure.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the webbing is restricted from withdrawing, then the occupant is properly positioned, but the anchor or buckle may still loosen under abnormal conditions causing secondary accidents

Engineering Contradiction:

Improveoccupant positioningVSAvoidanchor or buckle stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The sealed connection unit and multiple cable seals are pre-configured to maintain the stability of the anchor or buckle assembly. This preliminary sealing arrangement ensures that under abnormal conditions, the connection components remain stable and do not loosen, preventing secondary accidents.

Inventive Principle:

Principle #10Preliminary action

4Object-affected harmful factors

If a safety cover directs MGG emissions toward the vehicle body, then emissions are directed away from occupants, but if seats become rotatable this could endanger other passengers

Engineering Contradiction:

Improveemission direction controlVSAvoidseat rotation compatibility

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The potentially harmful gas emissions are converted into a contained force. The sealed connection unit transforms the harmful gas release into a beneficial contained pressure system that moves the piston to pull the anchor or buckle, eliminating the need for directional emission control while maintaining safety.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

Prevents gas emissions and part dislodgment, ensuring passenger safety under normal conditions and preventing secondary accidents during abnormal conditions.

Implementation Method 1

a fluid is generated through the ignition of the micro gas generator(MGG) by the impact of the vehicle

Methodology Applied

Scientific EffectIgnition: Combustion

Implementation Method 2

moving a portion of the connecting unit in one direction under pressure of the fluid received therein to pull the anchor or the buckle

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentUS12459461B2Lap pretensioner including a structure to limit gas emissions

Publication Date: 2025.11.04 WOOSHIN SAFETY SYST CO LTD

AI summary

The present invention relates to a lap pretensioner including a structure to limit gas emissions comprises a connecting unit connected with the anchor or the buckle; and a pressure unit having an interior space formed therein into which a portion of the connecting unit is inserted, actuated by an impact on the vehicle to inject a fluid into the interior space, and moving a portion of the connecting unit in one direction under pressure of the fluid received therein to pull the anchor or the buckle; wherein the pressure unit is provided inside the interior space, and configured to allow fluid to move along the inside of a variable space that varies in response to the movement of the connecting unit.