Vehicle Door Latch Restriction Mechanism for Collision Opening Prevention

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Solution Overview

Problem

Existing door latch devices fail to securely prevent accidental door opening when impact force is applied to a vehicle due to collisions, as the inertia lever part can return to the operating position despite initial displacement.

Innovation Solution

A door latch device with an open link, inertia lever part, and restriction mechanism that prevents the inertia lever part from returning to the operating position during impact, ensuring the ratchet lever does not release the latch even if the door handle is operated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inertia lever part is allowed to return to the operating position after impact, then the door handle can resume normal operation, but the door may be accidentally opened during collision

Engineering Contradiction:

Improvedoor security during collisionVSAvoiddoor handle operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The restriction mechanism is pre-configured to automatically activate when the inertia lever part moves to the non-operating position during impact, preventing its return to the operating position and thereby preemptively blocking the door opening path before accidental opening can occur

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The restriction mechanism acts as an intermediary component between the inertia lever part and the ratchet lever, controlling whether the operation force from the door handle can be transmitted to the ratchet lever based on the impact state

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the restriction mechanism prevents the inertia lever part from returning to the operating position, then accidental door opening is prevented, but the door handle cannot be operated even after impact

Engineering Contradiction:

Improvedoor security during collisionVSAvoiddoor handle operation duration

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The system dynamically transitions between two operational states: normally the inertia lever part can return to the operating position for standard door handle operation, but during impact it moves to the non-operating position where the restriction mechanism activates to prevent return, creating a conditional operational state based on impact detection

Inventive Principle:

Principle #15Dynamics

3Speed

If the inertia lever part is energized by the release energizing spring, then it returns to the operating position quickly, but the door may be accidentally opened multiple times during impact

Engineering Contradiction:

Improveinertia lever part return speedVSAvoiddoor security during collision

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The restriction mechanism is pre-positioned to block the return path of the inertia lever part before the release energizing spring can complete its full energizing action, preventing the lever from returning to the operating position and thereby stopping the cycle of accidental door opening before it can occur

Inventive Principle:

Principle #9Preliminary anti-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 prevents accidental door opening during collisions by maintaining the inertia lever part in a non-operating position, securing the door in a closed state.

Implementation Method 1

a release energizing member configured to energize the inertia lever part to be maintained at the operating position with respect to the lever main body

Methodology Applied

Scientific EffectElastic force: Elasticity

Implementation Method 2

an inertia lever part supported by the lever main body so as to be displaceable between an operating position and a non-operating position

Methodology Applied

Scientific EffectInertia: Inertia

Data Source

PatentUS12523069B2Door latch device

Publication Date: 2026.01.13 HI-LEX ACT CORP

AI summary

A door latch device includes: an open link including a lever main body, an inertia lever part, and a release energizing member configured to energize the inertia lever part to be maintained at an operating position with respect to the lever main body, an operation force of the door handle being not transmitted to the ratchet lever even in a state in which the lever main body is disposed at an unlocked position, in a case where the inertia lever part is disposed at a non-operating position against energizing force of the release energizing member; a ratchet lever; and a restriction mechanism disposed between the lever main body and the inertia lever part, the restriction mechanism being configured to restrict returning movement to the operating position in a case where the inertia lever part moves to the non-operating position.