Vehicle Bonnet Safety Device Wedge Mechanism

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Solution Overview

Problem

Existing bonnet lifting safety devices for vehicles require special mountings and have high replacement costs due to shear pins that need to be replaced after activation, limiting their versatility and increasing maintenance expenses.

Innovation Solution

A safety device with a wedge-shaped drive element and guide surface that pivots the bonnet support members apart upon activation, using a pyrotechnic squib and a deformable design to lift the bonnet, allowing for universal vehicle application and reducing replacement costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a prior bonnet lifting arrangement with shear pin is used, then the bonnet can be lifted in a crash situation, but the shear pin must be replaced after activation which adds to repair cost

Engineering Contradiction:
Improvebonnet lifting functionVSAvoidreplacement cost
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent uses a disposable shear pin that is designed to fail at a predetermined load. After activation, the shear pin breaks but the drive means remains functional and can be reused. This replaces only the cheap shear pin rather than the entire expensive assembly, resolving the contradiction between maintaining reliability and reducing repair costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If a prior bonnet lifting arrangement with special mountings is used, then the drive means can be mounted to the vehicle, but the arrangement is limited to vehicles with these special mountings

Engineering Contradiction:
Improvemounting stabilityVSAvoidvehicle compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent designs the drive means with a universal mounting system that can be adapted to different vehicle types without requiring special pre-installed mountings. The mounting member can be attached to various vehicle structures, making the bonnet lifting device compatible with multiple vehicle models and enhancing versatility while maintaining mounting stability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If a wedge-shaped drive element with guide surface is used, then the support members can be pivoted apart to lift the bonnet, but the drive element must be driven with sufficient force to overcome the guide element retention

Engineering Contradiction:
Improvebonnet lifting mechanismVSAvoiddrive force required
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent incorporates a retention feature in the guide surface that holds the guide element in place during normal operation. Upon activation, a predetermined break feature breaks first, allowing the guide element to be released and driven along the guide surface. This preliminary retention and controlled release mechanism ensures the bonnet lifting mechanism operates smoothly with the required force only when needed.

Inventive Principle:
Principle #10Preliminary action

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 device effectively lifts the bonnet to create distance between the bonnet and engine block, enhancing pedestrian safety without the need for special vehicle adaptations and minimizing maintenance costs by using a reusable and deformable mechanism.

Implementation Method 1

the drive element having a substantially wedge-shaped portion and a guide surface which is inclined at an angle relative to the drive direction

Methodology Applied
Scientific EffectWedge: Wedge

Implementation Method 2

a pyrotechnic squib and a deformable design to lift the bonnet

Methodology Applied
Scientific EffectExplosion: Explosion

Data Source

PatentEP2423056B1A safety device
Publication Date: 2013.03.13 AUTOLIV DEV AB
  • EP2423056B1 patent drawingFigure 1~3
  • EP2423056B1 patent drawingFigure 4~7

AI summary

A safety device for use in a vehicle, the device comprising: a first support member which incorporates a mounting member which is configured to be mounted to the bonnet of a vehicle; a second support member which is configured to be mounted to part of a vehicle, the first and second support members being attached to each other pivotally; a drive arrangement, having a housing which is attached to one of the first and second support members and a drive element which may be driven with respect to the housing in a drive direction, the drive element having a guide surface which is inclined at an angle relative to the drive direction; and a guide element mounted on the other of the first and second support members, wherein, in an initial position, the guide element is at a first location on the guide surface and, to move from the initial position to an activated position, the drive element is driven with respect to the housing so that the guide element is driven along the guide surface from the first location to a second location, and the guide surface exerts a force on the guide element to drive the first and second support members away from one another in the region of the guide element, and to pivot the first and second support members with respect to one another.