Vehicle Headrest Two-Point Contact Whiplash Protection
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Solution Overview
Problem
Conventional headrests, including crash-active systems, often fail to adequately protect against whiplash injuries due to reliance on occupant mass or expensive pyrotechnic mechanisms, and existing designs do not sufficiently reduce the risk of cervical spine injuries during rear-end collisions.
Innovation Solution
A headrest design featuring a foam base with distinct dynamic properties and a crash beam integrated into the headrest frame, allowing for a two-point contact system that stabilizes the head and reduces the whiplash effect by altering the distribution of forces and torque during impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a crash-active headrest with large distance between head and headrest in normal operation is used, then headroom comfort is improved, but the risk of cervical spine injury in rear-end collision increases
Solution Approach 1:
The headrest is designed with dynamic movement capability through a shock-absorbing mechanism that allows the headrest to actively move forward upon detection of rear-end collision. This transforms the static headrest into a dynamic system that adapts its position based on collision conditions, reducing the distance between head and headrest when needed while maintaining larger distance during normal operation for comfort.
Solution Approach 2:
The headrest system incorporates preliminary action by pre-positioning the headrest at an optimal distance for comfort and pre-configuring the shock-absorbing mechanism to activate automatically upon collision detection. The system is prepared in advance with sensors and mechanical components positioned to immediately reduce the head-to-headrest distance when a rear-end collision occurs, eliminating the need for manual intervention.
2Extent of automation
If body-triggered inertial mass activation is used, then headrest shift is achieved, but reliability for low body weight occupants deteriorates
Solution Approach 1:
The patent introduces an intermediary sensor system that detects rear-end collision forces independently of occupant body mass. This intermediary detection mechanism triggers the headrest activation separately from the traditional body-triggered inertial method, ensuring reliable activation for all occupants regardless of their weight. The sensor acts as a mediator between the collision event and the headrest response, decoupling the activation reliability from occupant mass variations.
3Speed
If externally triggered pyrotechnic gas generator is used, then headrest activation speed is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the pyrotechnic gas generator and complex sensor system from the headrest activation mechanism, replacing them with a simplified mechanical shock-absorbing system. This extraction removes the expensive and complex external triggering components while retaining the essential function of rapid headrest activation through purely mechanical means that respond automatically to collision forces.
Solution Approach 2:
The invention replaces expensive, complex pyrotechnic components with simpler, more economical mechanical elements. The shock-absorbing mechanism uses readily available mechanical components that are less costly and simpler than pyrotechnic systems, achieving the same protective function through a more economically viable and less complex design.
4Extent of automation
If pivoting mechanism with inertia sensor and bending spring is used, then headrest movement is achieved, but reaction time increases
Solution Approach 1:
The patent eliminates the multi-stage activation process involving inertia sensors and bending springs by implementing a direct mechanical shock-absorbing mechanism. This allows the headrest to respond immediately to collision forces without the time-consuming sequential activation steps of sensor detection, signal processing, and mechanical triggering, thereby rushing through the activation process in a single direct mechanical response.
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 headrest effectively reduces the risk of whiplash and cervical spine injuries by providing enhanced stabilization and guidance of the head during crashes, potentially eliminating the need for expensive active systems and ensuring protection across a range of occupant weights.
Implementation Method 1
a foam base body surrounding the headrest frame/headrest box (14), with a dynamic behavior of the foam base body (36)
Implementation Method 2
a crash beam (26, 28, 30, 32, 36) arranged in the lower area at a second height of the headrest frame/headrest box (14) inside the foam base body (36)
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
The invention relates to a headrest (10) for a vehicle seat, in particular for a backrest of a motor vehicle seat, said headrest essentially comprising a headrest frame or headrest casing (14) and a foam base body (36) that surrounds the headrest frame or casing (14). In the event of a rear impact on the motor vehicle, the headrest remains fixed in relation to the backrest (conventional headrest) or at least part of the headrest is immediately displaced towards the vehicle occupant (active headrest). According to the invention, the head of a vehicle occupant can be brought into contact with the headrest (10) at least at two different heights (k1z, k2z), (two-point contact), to reduce or neutralise a torque (My) about a y-axis (y-y) in the vicinity of the vertebral column and to prevent accident-related injuries to the seat occupant, in particular to prevent cervical spine syndrome or a whiplash injury in the event of a front and/or rear impact. A head centre of gravity (HCG) is also configured between the two heights (k1z, k2z) of the headrest (10).