Automotive Seat Headrest Support with Energy Absorbing Locking Mechanism
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Solution Overview
Problem
Current automotive seat headrests do not effectively slow down the rearward motion of a passenger's head during a collision and fail to lock the headrest in a deflected position after the impact, potentially causing the headrest to push forward against the passenger.
Innovation Solution
The automotive seat headrest assembly features a pair of headrest supports with an absorption unit comprising helically coiled wire components that allow angular deflection under bending forces and lock in a deflected orientation, using a second helical element to secure the first component in the deflected position, thereby absorbing energy and preventing forward movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a rigid headrest support is used, then the headrest can maintain its position and provide support, but it cannot gradually slow down rearward motion and absorb energy during a collision
Solution Approach 1:
The support mechanism changes its mechanical parameters dynamically: during normal conditions it maintains rigid support, but during collision it transitions to an energy-absorbing state through controlled deformation of the rod and engagement of the locking mechanism, allowing it to gradually slow rearward motion while absorbing energy
Solution Approach 2:
The headrest support transitions from a static rigid structure to a dynamic system that can absorb energy through controlled deformation. The rod bends under collision forces, and the locking mechanism engages at specific deflection points, creating a dynamic response that gradually slows rearward motion while maintaining structural integrity
2Reliability
If a headrest support allows deflection during collision, then it can absorb energy, but it may fail to lock in the deflected position and push forward against the passenger
Solution Approach 1:
The locking mechanism is self-actuating based on the deflection of the rod. When the rod deflects during collision, the locking mechanism automatically engages at the appropriate position without requiring external control systems, ensuring reliable position locking while maintaining relatively simple structure
Solution Approach 2:
The absorption unit acts as an intermediary between the rod and the locking mechanism. It translates the mechanical energy of collision into controlled deflection, which then triggers the locking mechanism to engage, ensuring reliable position locking while managing the complexity of the overall system
3Ease of manufacture
If the headrest support structure is simplified, then it is easier to manufacture, but it cannot effectively lock the headrest in a deflected position after impact
Solution Approach 1:
The support mechanism is segmented into distinct functional components: the rod, the absorption unit, and the locking mechanism. This segmentation allows each component to be manufactured separately using standard processes, while their integration provides reliable position locking functionality
Solution Approach 2:
The absorption unit uses a rod that is designed to undergo controlled deformation during collision. This sacrificial element absorbs energy through its deformation and then locks in place, providing reliable position locking while being manufacturable using simple processes
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 gradually slows down the headrest's rearward motion during a collision, absorbs energy, and locks the headrest in a deflected position, preventing it from pushing forward against the passenger's head, enhancing safety by maintaining the headrest's position after forces dissipate.
Implementation Method 1
the absorption unit adapted to allow angular deflection of the upper rod relative to the lower rod when a bending force is applied to the upper and lower rods, and to hold the lower and upper rods in a deflected orientation when the bending force is removed
Implementation Method 2
each second component is a helical element comprising a length of helically coiled wire encircling the associated first component and extending longitudinally along an entire length of the associated first component, and upon deflection of the first components, coils of the second components slide into the gaps formed between adjacent coils of the first components on an outside of the deflected first components to lock the first components in the deflected orientation
Data Source
AI summary
An automotive seat with headrest assembly includes a seatback, a headrest, and a pair of headrest supports adapted to support the headrest on the seatback, each of the headrest supports including a lower rod, an upper rod, and an absorption unit positioned between and interconnecting the lower rod and the upper rod, the absorption unit adapted to allow angular deflection of the upper rod relative to the lower rod when a bending force is applied to the upper and lower rods, and to hold the lower and upper rods in a deflected orientation when the bending force is removed from the upper and lower rods.