Latch Assembly Actuation Speed Reliability

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Solution Overview

Problem

Current vehicle safety systems face challenges in actuation speed, actuation power requirements, and high replacement costs, particularly with chemical or explosive charge-based systems, which compromise safety, reliability, and reusability.

Innovation Solution

A latch assembly with a mechanical energy storage system, mechanical advantage system, and trigger system that moves a closure panel from a closed to an open position, utilizing stored mechanical potential energy and amplifying trigger force to rapidly and reliably actuate safety mechanisms without the need for chemical or explosive charges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If chemical or explosive charge based actuation systems are used, then actuation speed is improved, but safety, reliability, and reusability deteriorate

Engineering Contradiction:
Improveactuation speedVSAvoidsafety and reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent replaces chemical/explosive actuation systems with a mechanical energy storage and release system. A spring-loaded latch mechanism stores mechanical energy in a biased state and releases it rapidly through a purely mechanical trigger, eliminating the need for chemical charges while maintaining fast actuation speed and improving safety and reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs preliminary action by pre-loading the latch mechanism in a biased state during normal operation. The spring is compressed and held ready to release, so that when a collision is detected, the stored mechanical energy can be immediately released without requiring chemical ignition or complex activation sequences, achieving both speed and reliability.

Inventive Principle:
Principle #10Preliminary action

2Speed

If chemical or explosive charge based actuation systems are used, then actuation speed is improved, but replacement costs deteriorate

Engineering Contradiction:
Improveactuation speedVSAvoidreplacement costs
Core Design Contradiction:
SpeedVSEase of manufacture

Solution Approach 1:

The patent employs a modular latch assembly where the trigger mechanism can be designed as a replaceable component. After deployment, only the trigger element needs replacement rather than the entire actuation system, significantly reducing replacement costs compared to chemical charge systems where the entire safety mechanism must be replaced.

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

Solution Approach 2:

The actuation system is segmented into modular components: the latch mechanism, the spring energy storage system, and the trigger element. This segmentation allows the trigger to be replaced independently after deployment, reducing replacement costs while preserving the expensive mechanical energy storage components.

Inventive Principle:
Principle #1Segmentation

3Reliability

If mechanical based actuation systems are used, then safety and reliability are improved, but actuation speed deteriorates

Engineering Contradiction:
Improvesafety and reliabilityVSAvoidactuation speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The mechanical latch system is pre-loaded with spring energy during normal operation, placing it in a ready-to-release state. When triggered, the stored mechanical energy provides rapid actuation speed without requiring complex mechanical assemblies or multi-step mechanisms, thus maintaining both safety/reliability and achieving fast response.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The latch mechanism is designed with asymmetric force characteristics: during normal operation, it maintains a strong locked state requiring significant force to open (ensuring safety). However, the trigger mechanism exploits a weak point or release path that allows rapid disengagement when activated, achieving fast actuation speed while maintaining structural integrity during normal use.

Inventive Principle:
Principle #4Asymmetry

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 solution provides rapid actuation and reduced replacement costs while ensuring safety and reliability, enabling effective pedestrian protection in vehicle collisions by moving the hood away from the engine block to prevent fatal injuries.

Implementation Method 1

a mechanical energy storage system having a device for storing mechanical potential energy for assisting the latch biasing element in moving the mating latch component from the latched position to the unlatched position

Methodology Applied
Scientific EffectMechanical potential energy storage: Spring

Implementation Method 2

a controllable current source for producing a current to heat the wire, which is caused to break and release the spring

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

a mechanical advantage system having a plurality of advantage elements for engaging the device, such that movement of the plurality of advantage elements is associated with a trigger force and cooperation of the plurality of advantage elements provides for amplification of the trigger force as an initiating force to release the stored mechanical potential energy

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP3431347B1Components for active pedestrian safety mechanism
Publication Date: 2020.06.24 MAGNA CLOSURES INC
  • EP3431347B1 patent drawingFigure 1A
  • EP3431347B1 patent drawingFigure 1B~1C
  • EP3431347B1 patent drawingFigure 1D~1E

AI summary

A latch assembly for driving a closure panel from a closed panel position to an open panel position. The latch assembly comprises: a latch mechanism having a first latch element for retaining a mating latch component in a latched position and for moving the mating latch component from the latched position to an unlatched position when released, the movement of the first latch element biased towards the unlatched position by a latch biasing element; and an actuation system having: a mechanical energy storage system having a device for storing mechanical potential energy for assisting the latch biasing element in moving the mating latch component from the latched position to the unlatched position; a mechanical advantage system having a plurality of advantage elements for engaging the device, such that movement of the plurality of advantage elements is associated with a trigger force and cooperation of the plurality of advantage elements provides for amplification of the trigger force as an initiating force to release the stored mechanical potential energy; and a trigger system configured to provide the trigger force to release the stored mechanical potential energy.