Rotary Latch Buckling for Secure Vehicle Door Locking

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Solution Overview

Problem

Conventional locking mechanisms for vehicle or building doors/hatches can fail to remain securely locked under excessive loads, such as those encountered in crashes, due to wear in linkages or Bowden cables, leading to unintended unlocking.

Innovation Solution

Incorporating a predetermined buckling point in the rotary latch with recesses on the catch arm, which increases the overlap between the rotary latch and pawl during excessive loading, ensuring the locking mechanism remains engaged and secure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the locking mechanism uses a conventional linkage or Bowden cable to connect the handle to the release lever, then the pivoting range of the release lever can be sufficiently large (20°-30°), but the linkage or Bowden cable may wear out due to age, reducing the pivoting range and risking unreliable opening

Engineering Contradiction:
Improvepivoting range of release leverVSAvoidreliability of opening mechanism
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent removes the intermediate linkage or Bowden cable from the system, directly connecting the handle to the release lever. This eliminates the wear-prone intermediate components while maintaining the necessary pivoting range, thus resolving the contradiction between ease of operation and reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If the locking mechanism is designed with a small pivoting angle requirement (10°-16°) for the release lever, then the opening operation becomes easier, but under excessive load (20-30 kN), the latching surface of the rotary latch may become detached from the pawl, causing unexpected opening

Engineering Contradiction:
Improvepivoting angle of release leverVSAvoidlatching strength under excessive load
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent introduces a blocking lever that proactively prevents the pawl from moving out of its locking position by blocking its path. This preliminary protective measure ensures that even under excessive loads, the latching surfaces remain engaged, resolving the contradiction between ease of operation and latching strength.

Inventive Principle:
Principle #9Preliminary anti-action

3Strength

If the locking mechanism uses a blocking lever to prevent unintended opening under excessive load, then the latching strength is improved, but the device complexity increases due to additional components

Engineering Contradiction:
Improvelatching strength under excessive loadVSAvoidnumber of components in locking mechanism
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines the blocking lever function with the existing release lever mechanism. The blocking lever is integrated into the same assembly, sharing common components and mounting points, thereby minimizing the increase in device complexity while achieving the desired latching strength under excessive load.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively prevents unintended unlocking by maintaining or increasing the overlap between the rotary latch and pawl under loads up to 30 kN, ensuring the locking mechanism remains securely latched even under excessive forces.

Implementation Method 1

the rotary latch includes a predetermined buckling point, which causes the distance between the free ends of the catch arm and the load arm of the rotary latch to increase in the latched state of the locking mechanism in the event of excessive loading

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2844812B1Lock for a flap or door
Publication Date: 2019.01.09 KIEKERT AG
  • EP2844812B1 patent drawingFigure 1

AI summary

The invention relates to a lock for a door or flap, comprising a locking mechanism that consists of a rotary latch (1) and at least one pawl (2) for locking the rotary latch (1), the rotary latch (1) when in the detent position preferably initiating an opening moment in the pawl (2). The design of the rotary latch (1) is such that said latch is deformed under excessive stress in the locked state in such a way that an engagement between the pawl (2) and the rotary latch (1) is maintained or increases. A lock of this type will not open even under excessive stress.