Vehicle Seat Folding Element with Yielding Stop Means
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Solution Overview
Problem
Existing vehicle seat designs with folding elements on the backrest pose a safety risk during frontal impacts, as they can act as rigid obstacles, increasing the Head Injury Criterion (HIC) beyond regulatory thresholds, and fail to ensure passenger safety without significantly increasing weight or compromising comfort.
Innovation Solution
A vehicle seat with a folding element, such as a shelf, mounted to pivot about an axis with stop means that allow it to assume a substantially vertical position and extend towards the front under impact, featuring increasing resistance mechanisms like elastic springs or locking pieces that yield under predetermined forces, ensuring the element does not obstruct the passenger's progression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a folding element (tray table) is fixed to the backrest in a vertical position, then it occupies minimal space and is easy to store, but it acts as a rigid obstacle during frontal impact, increasing head injury risk
Solution Approach 1:
The folding element is designed to pivot dynamically between a vertical stored position and a horizontal deployed position. During normal use, it remains vertical to minimize space. During impact, it can rotate forward to follow the passenger's head movement, converting from a rigid obstacle to a dynamic safety feature that reduces head injury risk.
Solution Approach 2:
The system changes the angular parameter of the folding element from 0 degrees (vertical) to 90 degrees (horizontal) based on impact conditions. The articulation mechanism allows the element to change its orientation parameter dynamically, transitioning from a space-saving configuration to a safety-oriented configuration during collision events.
2Strength
If the folding element is made rigid to maintain structural strength, then it provides stability, but it increases the force transmitted to the passenger's head during impact
Solution Approach 1:
The folding element maintains rigidity for structural stability during normal use but is designed to rotate dynamically during impact. The articulation mechanism allows the rigid element to change its angular position, following the passenger's head movement forward during collision, thereby reducing the relative velocity and impact force transmitted to the head.
Solution Approach 2:
The articulation mechanism acts as an intermediary between the rigid folding element and the passenger's head. It allows the rigid element to move in a controlled manner during impact, mediating the interaction between the structural component and the passenger to reduce harmful forces while maintaining the element's structural integrity.
3Adaptability or versatility
If the folding element is positioned horizontally for use, then it provides functionality for the passenger, but it obstructs the path of the passenger's head during frontal impact
Solution Approach 1:
The folding element is designed to be dynamic rather than static. During normal use, it can be positioned horizontally to provide functionality. During impact, it rotates forward to follow the passenger's head movement, eliminating obstruction. The system adapts its position based on operational vs. safety conditions.
4Object-affected harmful factors
If the seat back is made deformable to absorb impact energy, then it reduces head injury, but a rigid folding element fixed to it creates a conflict between energy absorption and structural support
Solution Approach 1:
The folding element is designed to pivot dynamically during impact, allowing it to follow the deformable seat back's movement while maintaining its own structural integrity. This dynamic configuration resolves the conflict between the deformable seat back's energy absorption function and the folding element's structural support role.
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 effectively reduces the risk of head injury during frontal crashes by allowing the folding element to pivot and absorb impact forces, maintaining safety without increasing the seat's weight or compromising comfort, thus meeting safety standards while optimizing passenger safety and comfort.
Implementation Method 1
at least one elastic spring, arranged behind the folding element, exerting a force on the folding element, in the event of pivoting of the folding element beyond a certain position
Implementation Method 2
positioned behind the folding element, comprising at least one element chosen from a foam material and an elastic spring
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
The transport vehicle seat makes it possible to avoid the violent impact of the head of a passenger located on the seat positioned behind and to dampen the violent rocking forward of this passenger in the event of a frontal impact of the transport vehicle. The seat has a pivot-mounted fold-down element (10), such as a tray, positioned on the rear face of a backrest. It has stop means (14) that keep the fold-down element (10) in a substantially vertical position, these stop means (14) being able to give during an impact applied to the fold-down element (10) and to allow the latter to continue swinging in the direction of the backrest to which it is fixed. The stop means has, relative to the substantially vertical position, increasing-resistance means that are able to keep the fold-down element (10) in the substantially vertical position, in the absence of said impact, and are able to allow the continuation of pivoting of the fold-down element under the effect of an impact.