Vehicle Seat Headrest Locking Mechanism Offset Suppression
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Solution Overview
Problem
Existing vehicle seat headrests face challenges in maintaining a locked state during strong impact forces, particularly when the locking mechanism is positioned off-center, leading to offset transformation and requiring high part and assembly accuracy to synchronize multiple locking mechanisms.
Innovation Solution
A vehicle seat headrest design featuring a single locking mechanism that fixes the headrest's rotation position and incorporates a stopper mechanism to regulate backward tilting, allowing infallible locking without high part or assembly accuracy, and reducing offset transformation through a combination of a rotary shaft, connecting parts, and biasing members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one locking mechanism is provided on the rotary shaft of the headrest, then the device complexity is reduced, but the reliability of suppressing offset transformation under strong impact force deteriorates
Solution Approach 1:
The invention divides the locking function into two independent parts: a locking mechanism and a stopper mechanism. The locking mechanism uses engagement hooks and engagement grooves to prevent forward tilting, while the stopper mechanism uses protrusions and recesses to prevent backward tilting. This segmentation allows each mechanism to focus on one direction of movement, improving reliability without requiring multiple locking mechanisms for all directions.
Solution Approach 2:
The invention introduces a stopper mechanism as an intermediary element that works alongside the locking mechanism. The stopper mechanism's protrusions engage with recesses in the rotary shaft to specifically handle backward tilting forces, while the locking mechanism handles forward tilting. This intermediary structure distributes the functional load and improves overall reliability.
2Reliability
If two locking mechanisms are provided on the rotary shaft to enhance strength, then the reliability of suppressing offset transformation is improved, but the device complexity and assembly difficulty increase
Solution Approach 1:
The invention segments the anti-tilting function into two specialized mechanisms: a locking mechanism for forward tilting prevention and a stopper mechanism for backward tilting prevention. This segmentation eliminates the need for multiple identical locking mechanisms, reducing device complexity while maintaining reliability.
Solution Approach 2:
Instead of using two locking mechanisms that both prevent forward tilting, the invention inverts the approach by using a stopper mechanism that specifically prevents backward tilting. This inverted design simplifies the overall structure while achieving the same reliability goal.
3Reliability
If two locking mechanisms are provided and synchronized, then the reliability is improved, but the manufacturing precision and assembly accuracy requirements increase
Solution Approach 1:
The invention segments the locking function into independent forward-tilting prevention (locking mechanism) and backward-tilting prevention (stopper mechanism). This segmentation eliminates the need for synchronization between multiple locking mechanisms, as each mechanism operates independently in its designated direction, thereby reducing manufacturing precision and assembly accuracy requirements.
4Device complexity
If the locking mechanism is provided in a biased position in the width direction, then the device complexity is reduced, but the offset transformation increases on the opposite side
Solution Approach 1:
The invention segments the stabilization function into two independent mechanisms positioned at different locations: the locking mechanism positioned to handle forward tilting forces and the stopper mechanism positioned to handle backward tilting forces. This segmentation allows each mechanism to counterbalance offset transformation in its respective direction, maintaining stability even with asymmetric positioning.
Data Source
AI summary
The purpose of the present invention is to provide a headrest to be infallibly locked when returned from a forward tilted position to a using position, without requiring high part accuracy and assembly accuracy. A vehicle seat headrest (4) according to the present invention, having: a stay (402) held on the seat back side; and a headrest main body (4A) supported forward rotatably from a using position with respect to the stay (402), includes: a locking mechanism (500) that fixes a rotation position of the headrest main body (4A) with respect to the stay (402) in the using position; and a stopper mechanism (600) that is not engaged with a regulation part in the using position, but is engaged with the regulation part when the headrest main body (4A) is tilted backward from the using position, to regulate backward tilting of the headrest main body (4A).