Multi-position Backrest Latch with Cam Blocking Element
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Solution Overview
Problem
Existing multi-position backrest latches in motor vehicles face challenges in securely locking the locking pin due to manufacturing and assembly tolerances, leading to play and reduced load absorption, especially under vehicle vibrations, and are not effective in providing comfort adjustments without rattle.
Innovation Solution
A latching device with a cam element that acts on a movable blocking element engaging over the locking pin, combined with a multi-pawl locking mechanism, ensures secure locking independent of the pawl, allowing for multiple comfort positions by using an additional blocking element and a spring-loaded control link for rigid and quiet operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional locking mechanism with catch and pawl is used, then the structure is simple, but manufacturing and assembly tolerances cause play between the locking pin and locking mechanism, reducing reliability
Solution Approach 1:
A cam element is introduced as an intermediary component between the locking pin and the locking mechanism. The cam element acts upon the locking pin in the direction of an open position, providing a controlled interaction that eliminates play caused by tolerances while maintaining overall structural simplicity.
Solution Approach 2:
The cam element changes the geometric parameters of the locking interaction by providing a controlled opening force on the locking pin. This parameter change ensures that the locking pin is properly positioned and play is eliminated without requiring a completely complex locking mechanism.
2Manufacturing precision
If the cam element acts directly on the locking mechanism, then the locking pin position is controlled, but the device complexity increases due to additional components
Solution Approach 1:
The cam element serves multiple functions: it acts upon the locking pin to control its position, provides a controlled opening force, and works in conjunction with the existing catch and pawl mechanism. This multi-functionality achieves precise locking pin positioning without proportionally increasing device complexity.
3Stability of the object's composition
If a fixed casing is used to prevent locking pin movement, then single position locking is achieved, but multi-position comfort adjustment is not possible
Solution Approach 1:
The system transitions from a static fixed casing to a dynamic cam element that can act upon the locking pin at different positions. The cam element's geometry allows it to provide controlled opening forces at multiple discrete positions, enabling comfort adjustments while maintaining stability through the controlled interaction.
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 provides a securely fixed locking pin in multiple positions, ensuring rigid locking and comfort adjustments without rattle, effectively absorbing vibrations and maintaining stability across climate conditions and component variances.
Implementation Method 1
comprising a cam element, which acts upon the locking pin in the direction of an open position
Implementation Method 2
a spring-loaded control link for rigid and quiet operation
Data Source
AI summary
A latching device for motor vehicle applications, in particular to a multi-position backrest latch for locking and unlocking seat backrests in motor vehicles. The basic structure of the device has a locking mechanism substantially consisting of a catch and pawls, and also has a locking pin that interacts with the locking mechanism, and a cam element, which acts upon the locking pin in the direction of an open position. According to the invention, the cam element acts on a blocking element which engages over the locking pin.