Inflatable Pelvis Restraint for Submarining Prevention

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Solution Overview

Problem

Existing safety restraint systems for vehicles, including inflatable seat belts and pelvis restraints, do not adequately address the need for improved occupant protection and comfort during impacts and rollovers, particularly in reducing contact pressure and preventing submarining of occupants.

Innovation Solution

A safety restraint device featuring an inflatable pelvis restraint system with a continuous webbing that extends across the seat cushion, incorporating a lap belt and shoulder belt portion, which can be inflated to increase seat cushion stiffness and prevent submarining by providing improved pelvic restraint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an inflatable pelvis restraint system is implemented, then pelvic protection and occupant safety are improved, but device complexity increases

Engineering Contradiction:
Improveoccupant safetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The inflatable restraint system is nested within the seat cushion structure, with the inflatable member positioned between the seat cushion and the occupant's pelvis. This integration allows the safety function to be embedded within the existing seat architecture, improving safety while managing complexity through thoughtful integration rather than adding entirely separate systems.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The inflatable member is pre-positioned within the seat cushion in a deflated or partially inflated state before impact occurs. Upon detection of a collision event, the system rapidly inflates the restraint to provide immediate pelvic support. This preliminary positioning allows the system to be ready for action without requiring complex real-time adjustment mechanisms during the impact event.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If the pelvis restraint portion is inflated to increase seat cushion stiffness, then submarining prevention is improved, but contact pressure between occupant and seat belt increases

Engineering Contradiction:
Improvesubmarining preventionVSAvoidcontact pressure
Core Design Contradiction:
Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The inflatable system provides localized stiffness enhancement specifically at the pelvis region where submarining prevention is critical, rather than uniformly increasing stiffness across the entire seat cushion. This localized approach prevents submarining while maintaining comfort in other contact areas through differential firmness distribution.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The seat cushion transitions from a soft, compliant state during normal operation to a dynamically stiffened state during impact events through rapid inflation of the restraint portion. This dynamic adjustment allows the cushion to adapt its mechanical properties based on operational conditions, providing firm support when needed while maintaining comfort during normal use.

Inventive Principle:
Principle #15Dynamics

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 inflatable pelvis restraint system effectively reduces contact pressure between the occupant and the seat belt, enhances pelvic protection, and prevents submarining by increasing seat cushion stiffness and angle, thereby improving overall occupant safety during vehicle impacts and rollovers.

Implementation Method 1

The pelvis restraint portion is inflatable and adapted to extend across the seat cushion between a first lateral side of the seat and a second lateral side of the seat

Methodology Applied
Scientific EffectGas inflation: Pressurisation

Data Source

PatentEP3186112B1Safety restraint system with inflatable pelvis restraint device
Publication Date: 2022.03.02 AUTOLIV ASP INC
  • EP3186112B1 patent drawingFigure 1
  • EP3186112B1 patent drawingFigure 2
  • EP3186112B1 patent drawingFigure 3

AI summary

A safety restraint system for a vehicle seat having a seat back, a seat cushion and a frame includes an inflatable pelvis restraint device having a flexible member extending laterally across the seat cushion and having a first end and a second end. The flexible member includes at least a portion that is inflatable for increasing a height of the seat proximate a forward edge of the seat. In one embodiment, both the first and second ends are attached to the frame. In another embodiment, the safety restraint system includes a continuous webbing that defines a pelvis restraint portion, a lap belt portion and a shoulder belt portion. The lap belt portion, the shoulder belt portion, or both may be additionally inflatable.