E-latch Mechanical Override for Power Failure Egress

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Solution Overview

Problem

Current vehicle door latch systems with electronic backup features are expensive, increase weight, and fail to effectively provide a child lock and two-motion release during power failures or accidents, leading to potential passenger entrapment and legal non-compliance.

Innovation Solution

A latch assembly with a releasing lever, hold open lever, and override assembly that requires two distinct movements to unlock the door during power failures, utilizing a single motor and eliminating the need for a backup power source, while maintaining a child lock feature and preventing accidental unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a completely electronic backup system is used, then the door can be opened during power failure, but the system becomes expensive and heavier due to requiring separate power sources and electronic controllers

Engineering Contradiction:

Improvedoor opening capability during power failureVSAvoidsystem cost and weight

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the proposed electronic backup system (battery, controller, sensors) with a purely mechanical override system. The mechanical release lever and cam mechanism provide door opening capability during power failure without requiring any additional power sources or electronic components, thus reducing system cost and weight while maintaining reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The mechanical override system is self-contained and does not require external power sources, controllers, or sensors. The spring-loaded cam mechanism automatically provides door opening capability when the release lever is actuated, making the system independent and eliminating the need for expensive electronic backup components.

Inventive Principle:

Principle #25Self-service

2Reliability

If a mechanical release lever is used for backup, then the door can be opened manually, but the release mechanism may be located in non-obvious positions making it difficult to find during emergencies

Engineering Contradiction:

Improvemanual door opening capabilityVSAvoidlocatability of release mechanism

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The release lever is integrated into the existing interior door handle assembly, combining the emergency release function with the normal door opening mechanism. This ensures the release mechanism is always in an obvious, easily locatable position (at the door handle) rather than being a separate hidden component, while maintaining manual door opening capability during emergencies.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the backup system is always engaged, then the door can be opened during power failure, but child lock and two-motion release features cannot be effectively provided

Engineering Contradiction:

Improvedoor opening capability during power failureVSAvoidchild lock and two-motion release functionality

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system dynamically adapts its behavior based on power availability. When power is present, the electronic control system manages locking and child lock features normally. When power fails, the mechanical override system becomes active, allowing door opening through the release lever. This dynamic switching enables both safety features (child lock when powered) and emergency access (mechanical override when unpowered).

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The emergency door opening function is extracted as a separate mechanical subsystem that operates independently of the electronic control system. This extracted mechanical override does not interfere with electronic child lock or two-motion release features when power is available, but provides independent door opening capability when power fails, resolving the conflict between always-engaged backup and adaptive safety features.

Inventive Principle:

Principle #2Taking out (Extraction)

4Adaptability or versatility

If a second motor is used to control the backup system, then child lock and two-motion release can be maintained, but the system may remain engaged after accidents or power failure increasing entrapment risk

Engineering Contradiction:

Improvechild lock and two-motion release maintenanceVSAvoiddoor opening reliability after power failure

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the second motor-controlled backup system with a passive mechanical override mechanism. The spring-loaded cam and release lever system requires no power source and cannot remain engaged due to power loss. The mechanical system naturally returns to the unlocked position when the release lever is actuated, ensuring reliable door opening after accidents or power failure without the entrapment risk of motor-controlled systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10844639B2E-latch with mechanical backup and electronic override cancel feature

Publication Date: 2020.11.24 HYUNDAI AMERICA TECHNICAL CENTER INC

AI summary

A latch assembly and a method of disengaging the latch assembly for a vehicle door are provided. In particular, the latch assembly includes a releasing lever that is moveably attached to the latch assembly via a pawl and is moveable between an engaged and disengaged position to unlatch the latch assembly. Additionally, a lock lever interacts with an override assembly to control whether the vehicle door is opened. The override assembly requires two movements to move the lock lever to an unlocked position and to open the latch during a power failure.