Vehicle Headrest Latch Mechanism for Crash Safety
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Solution Overview
Problem
In vehicle headrests, the latching mechanism between support rods and guides fails during seat back deformation in accidents, leading to safety concerns as the latch element moves out of the notch, compromising the secure latching of the support rod.
Innovation Solution
A headrest design featuring a latch system with a movable latch element that includes a notch and a latching part, allowing for secure engagement even during relative rotation between the support rod and guide, utilizing a pivot mechanism and biasing elements to maintain latching, ensuring the support rod remains locked in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed latch element is used in the guide, then the structure is simple, but the latching fails during seat back deformation as the latch element moves out of the notch
Solution Approach 1:
The latch element is made movable relative to the guide through a pivot joint, allowing it to dynamically adjust its position. This dynamic capability enables the latch element to maintain engagement with the notch even when the guide rotates during seat back deformation, resolving the contradiction between simple structure and reliable latching under deformation conditions.
Solution Approach 2:
A biasing element is introduced to preliminarily position the latch element in the notched position before any deformation occurs. This preliminary action ensures that the latch element is pre-loaded into the notch, and the biasing element continuously exerts force to maintain this engagement, preventing disengagement during subsequent deformation events.
2Reliability
If the latch element is made movable to maintain engagement during rotation, then latching reliability improves, but the device complexity increases
Solution Approach 1:
The latch element is made movable relative to the guide through a pivot joint, allowing it to dynamically adjust its position. This dynamic capability enables the latch element to maintain engagement with the notch even when the guide rotates during seat back deformation, resolving the contradiction between simple structure and reliable latching under deformation conditions.
Solution Approach 2:
A pivot joint is introduced as an intermediary mechanism between the latch element and the guide. This intermediary allows controlled relative movement, enabling the latch element to adapt to guide rotation while maintaining notched engagement, thus achieving reliable latching without requiring a completely complex mechanism.
3Object-affected harmful factors
If a pivot mechanism with biasing element is added to maintain latching during rotation, then safety is enhanced, but manufacturing complexity increases
Solution Approach 1:
A pivot joint is introduced as an intermediary mechanism between the latch element and the guide. This intermediary allows controlled relative movement, enabling the latch element to adapt to guide rotation while maintaining notched engagement, thus achieving reliable latching without requiring a completely complex mechanism.
Solution Approach 2:
The biasing element automatically maintains the latch element in the notched position through its inherent elastic force, without requiring external actuation or complex control systems. The mechanism serves itself by using the biasing element's natural tendency to return to a preferred position to continuously ensure latching engagement, simplifying manufacturing while enhancing safety.
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 ensures the support rod remains securely latched during seat back deformation, maintaining safety standards by preventing axial movement and rotation-induced disengagement, thus enhancing passenger safety in accidents.
Implementation Method 1
the latch element is pivotal about a pivot axis. This can include embodiments in which the latch element is mounted by a pivot joint
Implementation Method 2
The latch element can be biased into the starting position by a biasing element
Data Source
AI summary
A head rest is illustrated and described that has a head box (11) by which at least one support rod (12) can be secured to a vehicle seat, wherein at least one end of the support rod (12) is received in a bearing (14) carried on the head box (11) or the vehicle seat, wherein the support rod (12) can be latched releasably to at least one bearing (14) by a latch (15) movable between a latching position and a release position, wherein the latch (15) has at least one notch (16) that extends over a region of the circumference of the support rod (12) and has a latch element (17) carried by the bearing (14).The special feature is that the latch element (17) is movably mounted, so that in the latching position, in the event of a relative rotation between the support rod (12) and the bearing (14), it is movable out of a starting position into at least one crash position.