Motor Vehicle Door Lock Catch Lever Crash Inertia Blocking
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Solution Overview
Problem
Existing motor vehicle door lock systems face reliability issues due to unintentional opening during crashes, caused by inertia forces, which can compromise safety features like side airbags, and existing solutions are prone to functional faults from corrosion or aging, making maintenance challenging.
Innovation Solution
A motor vehicle door lock design featuring a catch lever that remains permanently active, blocking the actuation lever unit during both normal operation and crashes, with an elastic coupling to the release lever, ensuring the catch lever retains its position and prevents unintended opening, even under high acceleration forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a catch lever is used to block the actuation lever unit during crashes, then reliability against unintentional opening is improved, but functional faults from corrosion or aging cannot be detected
Solution Approach 1:
The patent implements a feedback mechanism by coupling the catch lever's blocking state to the operation of the actuation lever unit. When the catch lever is in the blocking position, it prevents the actuation lever unit from moving, providing immediate feedback that the system is secured. This allows functional faults to be detected during normal operation attempts, as any abnormal resistance or failure in the catch lever's blocking action would be apparent when the actuation lever unit is operated.
2Reliability
If the catch lever is permanently active to block during crashes, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the catch lever mechanism with the existing actuation lever unit and release lever mechanism. The catch lever is integrated into the same housing and shares common mounting structures with the actuation lever unit. The elastic element coupling the catch lever to the release lever utilizes the existing movement and force transmission paths already present in the door lock system, thereby achieving permanent active blocking without significantly increasing overall device complexity.
Solution Approach 2:
The catch lever serves multiple functions: it blocks the actuation lever unit during crashes, provides a mechanical indication of the locked state, and works in conjunction with the release lever mechanism. The elastic element serving as a coupling mechanism also functions as a reset mechanism, automatically returning the catch lever to its blocking position after actuation. This multi-functionality reduces the need for separate components and simplifies the overall design.
3Reliability
If the catch lever blocks during normal operation, then protection against crash opening is improved, but ease of operation deteriorates
Solution Approach 1:
The catch lever is designed with dynamic characteristics through the elastic element coupling. During normal operation, when the release lever is actuated, the elastic element allows the catch lever to move from its blocking position to a released position, enabling door opening. During crashes, the inertia forces overcome the elastic coupling force, causing the catch lever to remain in the blocking position. This dynamic behavior allows the system to adapt to different operating conditions automatically.
Solution Approach 2:
The system utilizes parameter changes in the elastic element's force characteristics. The elastic element is designed with specific stiffness and pre-load parameters that allow the catch lever to be moved during normal operation but remain blocked under crash conditions. The force parameter of the elastic coupling is calibrated to be sufficient to return the catch lever to blocking position after actuation, yet insufficient to prevent blocking under high acceleration forces during crashes.
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 design enhances functional reliability by maintaining the catch lever's blocking position during crashes and allowing controlled opening during normal operation, ensuring the door lock remains secure and functional without requiring manual inspection or maintenance.
Implementation Method 1
the catch lever in non-deflected normal operation and in the event of a crash, blocks the actuation lever unit
Implementation Method 2
with an elastic coupling to the release lever, ensuring the catch lever retains its position
Data Source
AI summary
The invention relates to a motor vehicle door lock equipped with a locking mechanism (1, 2, 15), an actuation lever unit (3, 4) acting on the locking mechanism (1, 2, 15), and a catch lever (10). The catch lever (10) renders the actuation lever unit (3, 4) ineffective, at least when acceleration forces of a given magnitude occur, e.g. in case of an accident (crash). According to the invention, the catch lever (10) blocks the actuation lever unit (3, 4) during non-deflected normal operation and in the event of a crash while releasing the actuation lever unit (3, 4) only for deflected normal operation.