Vehicle Seat Fitting With Self-Locking Pawl for Play-Free Backrests
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Solution Overview
Problem
Existing vehicle seat backrest fittings with blocking mechanisms exhibit manufacturing and assembly tolerances that result in residual play, which is undesirable and can lead to unintended movement during normal use and crashes.
Innovation Solution
A vehicle seat fitting with a blocking mechanism that includes a fixed blocking disk and a pivotably mounted pawl, secured by a friction lobe system with different angles of friction, eliminating play through a self-locking mechanism that compensates for tolerances without requiring additional assembly adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blocking mechanism with pawl and blocking disk is used, then the backrest can be locked in position, but residual play occurs due to manufacturing and assembly tolerances
Solution Approach 1:
The patent changes the friction parameter by introducing a friction lobe with a specific friction angle (α) between the pawl and blocking disk. This friction-based parameter modification allows the blocking mechanism to compensate for manufacturing and assembly tolerances, eliminating residual play while maintaining reliable locking stability.
2Manufacturing precision
If a separate adjustable stop is added to eliminate play, then bearing point play is removed, but assembly complexity increases
Solution Approach 1:
The patent extracts the play elimination function from a separate adjustable stop component and integrates it into the blocking disk itself through the friction lobe. This integration removes the need for additional adjustable elements, simplifying the assembly process while effectively eliminating bearing point play.
Solution Approach 2:
The friction lobe is merged with the blocking disk as an integral component, combining the locking function and play elimination function into a single element. This merging reduces the number of parts and eliminates the need for separate adjustment mechanisms, thereby reducing assembly complexity.
3Stability of the object's composition
If the pawl is centered on the blocking disk, then form-fitting engagement is achieved, but radial play persists at the bearing point
Solution Approach 1:
The patent introduces a friction angle parameter (α) between the pawl and blocking disk contact surfaces. This friction parameter creates a self-centering effect that eliminates radial play at the bearing point while maintaining form-fitting engagement, without requiring additional adjustment mechanisms.
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 play-free and crash-resistant locking mechanism that ensures stable backrest positioning during normal use and in crash scenarios, eliminating the need for complex assembly adjustments.
Implementation Method 1
a friction lobe (22, 36) which presses, by means of friction, the pawl (20) against the blocking disk (18)
Data Source
AI summary
A fitting for a vehicle seat with a first seat element and a second seat element. The fitting includes a first fitting adapter, which is arranged fixedly on the first seat element, with a locking disc, and a second fitting adapter, which is mounted pivotably in relation to the first fitting adapter, with a locking pawl. The locking pawl is mounted on a first bearing point of the second fitting adapter so as to be pivotable between an open position releasing the pivoting movement and a locking position locking the pivoting movement. In the locking position, the locking pawl engages in a form-fitting manner at least in part in a locking receptacle of the locking disc, and the locking disc has a stop on which the first bearing point is supported.