Self-Cancel Lever Mechanism for Automobile Door Latch
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Solution Overview
Problem
Automobile door latch assemblies often inadvertently lock when users attempt to lock the door without a key, leading to inconvenience and potential issues with door operation.
Innovation Solution
A latch assembly with a self-cancel lever mechanism that automatically unlocks the door when it is closed, using a lock link and door ajar cam to prevent inadvertent locking, and allows keyless locking functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a lock lever is used to lock the door without a key, then keyless locking functionality is enabled, but inadvertent locking occurs leading to door operation issues
Solution Approach 1:
A self-cancel lever is introduced as an intermediary component between the lock lever and the locking mechanism. This self-cancel lever automatically disengages the locking mechanism under specific conditions (when the door is properly closed), thereby preventing inadvertent locking while preserving keyless locking capability. The self-cancel lever acts as a safety mediator that overrides the lock lever's locking action when closing conditions are met.
2Reliability
If a self cancel lever mechanism is added to prevent inadvertent locking, then door operation reliability is improved, but device complexity increases
Solution Approach 1:
The self-cancel lever mechanism is integrated into the existing latch assembly structure, merging the new safety function with the existing lock lever, lock link, and door ajar cam components. Rather than adding a completely separate system, the self-cancel lever is incorporated into the current mechanical linkage, allowing it to interact with existing components to achieve automatic unc locking while minimizing overall structural complexity.
3Reliability
If the lock link translates to cancelling position via self cancel lever, then inadvertent locking is prevented, but the locking mechanism requires additional movement steps
Solution Approach 1:
The self-cancel lever is positioned and configured in advance within the latch assembly, with its geometry and engagement points predetermined. When the door closes under normal conditions, the door ajar cam automatically triggers the self-cancel lever to translate the lock link to the cancelling position before the locking mechanism can engage. This preliminary positioning ensures that inadvertent locking is prevented without requiring additional user actions or complex sequencing.
Data Source
AI summary
A latch assembly for use with a door includes a lock lever to lock the door in a locked position and to unlock the door in an unlocked position, a door ajar cam to rotate between a door open position in response to a door open condition and a door closed position in response to a door closed condition, a self cancel lever releasably engaged to the door ajar cam, wherein the self cancel lever is operated in response to the door ajar cam rotating to the door closed position, and a lock link selectively engaged to the self cancel lever, wherein the lock link is translated to a cancelling position in response to the self cancel lever operated from the door ajar cam.