Vehicle Seat Headrest Locking Mechanism Crash Safety
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Solution Overview
Problem
Existing vehicle seat headrest adjustment devices lack sufficient crash safety and smooth operation due to compromised design that impairs both adjustability and crash protection.
Innovation Solution
An adjustment device with a locking mechanism featuring a functional chain of a release lever, blocking element, and locking element, utilizing spring-biased active surfaces for secure locking and clamping, and a separate crash abutment mechanism to prevent unwanted unlocking during crashes, allowing for adjustable headrest positioning in both longitudinal and vertical directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a locking mechanism with spring-biased active surfaces is used to suppress clearance, then the firmness and free play suppression are improved, but the complexity of the locking device increases due to the functional chain of blocking element and locking element
Solution Approach 1:
The locking device is divided into functionally independent elements: a blocking element with a blocking surface and a locking element with a locking surface. These segmented components work together through a functional chain to suppress clearance, allowing each element to be optimized for its specific function while maintaining overall system firmness.
Solution Approach 2:
The blocking element is spring-biased into a default position where its blocking surface preliminarily contacts the locking surface of the locking element. This preliminary action ensures that clearance is suppressed before any adjustment or crash forces occur, maintaining continuous contact and firmness throughout the adjustment range.
2Reliability
If a unified locking mechanism is used for both normal operation and crash safety, then the device complexity is reduced, but the crash safety is compromised due to potential unwanted unlocking under strong forces
Solution Approach 1:
The locking mechanism is segmented into a first element (blocking element) for normal operation and a second element (locking element with crash abutment) for crash safety. This segmentation allows the normal locking function to operate with spring bias while the crash abutment provides independent protection against unwanted unlocking during collisions.
Solution Approach 2:
The crash abutment is designed to counteract the unwanted unlocking action that could occur during a crash. By providing a predetermined crash abutment surface that contacts the locking element, the mechanism preliminarily prevents the harmful effect of spring-biased unlocking under strong crash forces, ensuring the headrest remains securely locked.
3Ease of operation
If the active surfaces are designed for smooth sliding engagement, then the ease of operation is improved, but the crash safety is impaired due to potential loosening under strong longitudinal forces
Solution Approach 1:
The contact surfaces are segmented into two distinct functional zones: active surfaces for smooth sliding engagement during normal adjustment operations, and a separate crash abutment surface for providing rigid stopping force during crashes. This segmentation allows the active surfaces to be optimized for smooth operation while the crash abutment provides independent crash resistance.
Solution Approach 2:
The crash abutment surface acts as an intermediary element between the locking element and the release lever. During a crash, this intermediary surface provides a predetermined contact point that stops the locking element's movement, preventing the loosening that would otherwise occur through the smooth active surfaces under strong longitudinal forces.
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 high crash safety and robust adjustability by securely locking the headrest in place during normal use and preventing unwanted unlocking during crashes, while maintaining smooth operation and fine adjustability.
Implementation Method 1
The blocking element may be spring biased, in particular, into its default position so that its active blocking surface contacts the active locking surface of the locking element with spring bias
Implementation Method 2
sliding engagement as clamping surfaces, in particular, with one or both active surfaces being curved surfaces
Implementation Method 3
the locking element will end up, after a short acceleration path or safety distance respectively, in contact with a crash abutment surface on the release lever stopping the locking element
Data Source
AI summary
The present disclosure relates to an adjustment device for a head rest of a vehicle seat, including a locking device for adjusting a in relation to a back rest connection in a longitudinal direction and a vertical adjusting, where a locking device for locking the adjustment device is provided which comprises a release lever to be activated by the user which swivels a blocking element which in turn swivels a locking element.