Pyrotechnic Window Breaker Piston Actuation

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Solution Overview

Problem

Vehicle impact events can render occupant doors inoperable, and airbag deployments introduce hazardous byproducts into the cabin, necessitating a method to facilitate egress and reduce exposure to these byproducts.

Innovation Solution

A window breaker system comprising a housing, a pyrotechnic device, and a piston, where the piston moves from an undeployed to a deployed position upon actuation, shattering the window to allow egress and ventilation of airbag byproducts, controlled by a controller that detects predetermined conditions such as impact or airbag deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a pyrotechnic device is used to break the window, then the window can be shattered quickly to facilitate egress, but the device complexity increases

Engineering Contradiction:

Improvewindow breaking speedVSAvoidwindow breaker device complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The piston is nested within the housing, and the pyrotechnic device is disposed within the cavity of the housing. The piston moves within the cavity defined by the housing, creating a compact nested structure that reduces overall device complexity while maintaining rapid window-breaking capability

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The window breaker is divided into distinct functional segments: the housing structure, the pyrotechnic device, and the piston. This segmentation allows each component to be optimized independently and simplifies the overall device architecture, resolving the complexity issue while maintaining high-speed operation

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the piston moves from undeployed to deployed position to shatter the window, then egress is facilitated, but the force required increases

Engineering Contradiction:

Improveease of window removalVSAvoidforce required to shatter window

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The manual mechanical force required to break the window is replaced with a pyrotechnic actuation system. The pyrotechnic device generates thermal energy that rapidly expands the piston, converting chemical energy into mechanical force to shatter the window, thereby reducing the operational effort required

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The pyrotechnic device changes the physical parameters of the piston by heating it, causing rapid thermal expansion. This parameter change (temperature to volume expansion) generates the high force needed to shatter the window without requiring manual application of large forces

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the pyrotechnic device is actuated to move the piston, then the window is broken for ventilation, but the energy consumption increases

Engineering Contradiction:

Improveventilation effectivenessVSAvoidenergy consumed by pyrotechnic device

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The pyrotechnic device converts chemical energy stored in the pyrotechnic composition into useful mechanical work. The controlled combustion, which could be considered a harmful or dangerous process, is harnessed to generate the force needed to break the window and enable ventilation, thereby converting potential harm into benefit

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

Enables safe egress by removing windows and ventilating airbag byproducts, improving occupant safety and emergency exit in emergency situations.

Implementation Method 1

The piston may cooperate with the pyrotechnic device to form a combustion chamber therebetween such that a combustion event within the combustion chamber moves the piston within the cavity relative to the pyrotechnic device from an undeployed position to a deployed position

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS8727060B1Pyrotechnic window breaker

Publication Date: 2014.05.20 AUTOLIV ASP INC

AI summary

A window breaker is provided that may include a housing, a pyrotechnic device and a piston. The housing may include a slot and a cavity having a first end and a second end. The slot may extend through a wall of the housing and into the cavity. The pyrotechnic device may be fixedly attached to the housing and at least partially disposed in the cavity. The piston may be disposed in the cavity between the pyrotechnic device and the first end. The piston may be movable away from the pyrotechnic device within the cavity from an undeployed position to a deployed position in response to actuation of the pyrotechnic device.