Vehicle Headrest Latch Locking Against Crash-Induced Pivoting
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Solution Overview
Problem
Existing vehicle headrests can unintentionally pivot into a rest position due to inertial mass forces during a crash, compromising passenger safety by not maintaining the necessary support in the use position.
Innovation Solution
A safety device that moves between a locking and releasing position to firmly hold the latch element in the blocking position, preventing unintentional pivoting of the headrest, utilizing a holding element and engaging element with positive locking means, such as a U-shaped part with play, and an actuator for controlled movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the latch element is made movable between blocking and unblocking positions to enable headrest pivoting, then the ease of operation is improved, but the reliability deteriorates due to unintentional movement during crashes
Solution Approach 1:
The safety device applies a preliminary counteracting force to prevent the latch element from moving into the unblocking position during crash conditions. The holding element with positive locking means creates a preemptive barrier that counteracts inertial forces before unintentional pivoting can occur, while still allowing intentional actuation when needed.
Solution Approach 2:
The system transitions from a static locking mechanism to a dynamic one where the latch element can move between positions. The safety device introduces conditional dynamics by allowing movement only when intentionally actuated, while preventing movement under crash conditions through the positive locking mechanism.
2Reliability
If the latch element is held firmly in the blocking position to prevent unintentional pivoting, then the reliability is improved, but the ease of operation worsens due to difficulty in intentional release
Solution Approach 1:
The locking system is segmented into two independent functions: the latch element for blocking/unblocking and the safety device with holding element for securing/releasing. This segmentation allows the blocking function to be very secure while the releasing function remains accessible through the separate actuating mechanism.
Solution Approach 2:
The safety device acts as an intermediary between the latch element and the external actuation force. It transmits the intentional release command while blocking unintentional forces, mediating between the need for secure locking and easy release through its positive locking means that engage only with intentional actuation.
3Reliability
If positive locking means are added to the holding element to firmly secure the latch element, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The safety device is merged with the existing latch element mechanism, sharing common components such as the actuating mechanism and mounting structure. The positive locking means are integrated into the holding element rather than being separate add-on components, reducing overall complexity while maintaining enhanced reliability.
Data Source
AI summary
A vehicle headrest has a support defining a horizontal pivot axis and a cushion having a front face and pivotal about the axis on the support between a use position with the face upright and a rest position with the face generally horizontal. A latch element is displaceable in a longitudinal direction relative to the cushion between a blocking position operatively engaging the cushion and preventing the cushion from pivoting from the use position into the rest position and an unblocking position permitting such pivoting. A separate safety element engageable with the latch element is displaceable in a transverse direction between a locking position operatively engaging the latch element and preventing movement of the latch element into the unblocking position and a releasing position permitting movement of the latch element into the unblocking position.