Motor Vehicle Bonnet Locking Device with Overload Barrier
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Solution Overview
Problem
Existing motor vehicle bonnet locking devices cannot prevent damage to the bonnet during excessive closure speed, which can occur due to misuse, and may not adequately protect pedestrians in accidents.
Innovation Solution
A locking device with a catch and pawl mechanism that includes a catch hook with a barrier, allowing the striker to only submerge beyond the intended closed position in case of an overload, thereby preventing bonnet damage and ensuring pedestrian protection without additional components, while maintaining a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the locking device allows the striker to close freely without restrictions, then normal closure operation is smooth and quick, but the bonnet can be damaged during excessive closure speed or misuse
Solution Approach 1:
The barrier acts as an intermediary element between the striker and the bonnet. During normal closure, the striker passes the barrier without interference. During excessive closure speed, the barrier intervenes to limit the closure movement, preventing direct impact damage to the bonnet while still allowing the locking mechanism to engage.
Solution Approach 2:
The barrier changes the closure movement parameter by imposing a physical limit on the striker's travel distance. This parameter change ensures that under excessive closure speed conditions, the striker cannot penetrate beyond a safe distance, thereby preventing bonnet damage while maintaining normal closure functionality.
2Reliability
If the locking device includes additional components to prevent bonnet damage during misuse, then pedestrian protection is improved, but the device complexity and cost increase
Solution Approach 1:
The barrier serves multiple functions: it limits closure movement during excessive speed to prevent bonnet damage, and it also provides pedestrian protection by preventing the striker from penetrating too far into the bonnet structure. This multi-functionality eliminates the need for separate protective components, maintaining device simplicity while achieving dual protection goals.
Solution Approach 2:
The locking device protects itself from damage through the barrier, which automatically engages during excessive closure speed without requiring external control systems or additional protective components. The barrier is an integral part of the existing locking mechanism structure, making the system self-protecting.
3Reliability
If the catch hook is designed to allow full striker submersion, then pedestrian impact protection is maximized, but the bonnet can be damaged during misuse or excessive closure speed
Solution Approach 1:
The barrier allows partial striker submersion sufficient for pedestrian protection but prevents excessive submersion that would cause bonnet damage during misuse. The barrier is positioned at the exact distance that provides adequate crush zone for pedestrian safety while stopping short of causing structural damage to the bonnet.
Data Source
AI summary
A locking device for a motor vehicle bonnet, wherein the locking device comprises a locking mechanism with a rotary latch and a pawl for locking the rotary latch in a main latching position. Said locking device also comprises a catch hook which can define an opening movement of a lock retainer in a secure position which is between an intended closed position and an intended open position after opening the locking mechanism, wherein the catch hook comprises a load dependent barrier, and the locking device is designed such that a locking movement of the lock retainer is defined by the barrier in the intended closed position such that the lock retainer only goes in further than the intended closed position when there is an overload. A further developed locking device with pedestrian protection can also be provided.