Motor Vehicle Latch Pawl Retention via Torsional Spring Lever
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Solution Overview
Problem
Existing motor vehicle latches with locking mechanisms face challenges in reliably retaining the pawl in its starting position during the opening process, leading to potential unscheduled movements and reduced reliability.
Innovation Solution
A motor vehicle latch with a retaining device featuring an elastically rotated spring leg and spring lever, along with a downholder and stepped end, securely retains the pawl in its starting position through torsional moment and additional pre-tensioning, ensuring reliable retention during opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastically pre-tensioned spring is used to retain the pawl in its starting position during opening, then the pawl can be retained in its non-ratcheting starting position, but the retention reliability is insufficient and fault-prone
Solution Approach 1:
The retaining device is divided into multiple functional components: a spring lever with first and second arms, a separate elastically deformable leg, and a downholder. Each component performs a specific function - the spring lever provides leverage, the leg provides elastic retention force, and the downholder provides additional downward pressure. This segmentation allows each component to be optimized for its specific function, improving overall reliability without excessive complexity.
Solution Approach 2:
The patent combines multiple retention mechanisms into a single integrated device. The elastically deformable leg and the downholder work together to provide dual retention forces on the pawl. The spring lever merges the elastic force generation and the pawl engagement functions into one component. This merging creates a redundant retention system where multiple elements work together to ensure reliable pawl retention.
2Force
If the spring lever's first arm engages the pawl at a distance from its rotation axis, then the lever arm is increased and retention force is improved, but the space requirement and device complexity increase
Solution Approach 1:
The spring lever utilizes three-dimensional space efficiently by extending in multiple directions from the rotation axis. The first arm extends in one direction to engage the pawl, while the second arm extends in another direction to engage the elastically deformable leg. This multi-dimensional arrangement maximizes the lever arm length and retention force without requiring a proportional increase in the overall device volume.
Solution Approach 2:
The elastically deformable leg is positioned to be engaged by the spring lever's second arm, effectively nesting the leg within the spatial envelope of the spring lever assembly. The downholder is integrated into the same compact space. This nested arrangement allows multiple retention elements to occupy overlapping or adjacent spaces, reducing the total volume required compared to a distributed arrangement.
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 solution effectively retains the pawl in its starting position during opening, enhancing reliability and reducing the likelihood of faults compared to previous designs, with improved retention mechanisms such as the downholder and stepped end contributing to secure pawl positioning.
Implementation Method 1
The retaining device comprises a spring with an elastically rotated leg and a spring lever mounted thereon which can retain the pawl in its starting position during opening due to the elastic torsion
Implementation Method 2
The downholder holds the elastically rotated spring leg down in such a way that the pawl is thus retained in its starting position during opening in a further improved manner. In particular, the elastically rotated spring leg is also elastically bent and additionally pre-tensioned as a result of the holding down
Data Source
AI summary
A motor vehicle latch includes a retaining device which retains the pawl in its starting position with particular reliability during an opening process. The motor vehicle latch includes a locking mechanism encompassing a catch and a pawl for ratcheting of the catch. A retaining device is present which retains the pawl in its non-ratcheting starting position during opening. The retaining device encompasses a spring with an elastically rotated leg and a spring lever mounted thereon which can retain the pawl in its starting position during opening due to the elastic torsion. The pawl is retained in its starting position during opening with the aid of the spring lever and consequently with the aid of a torsional moment.