Dual-Occupant Seat Backrest Joint to Prevent Impact Separation

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Solution Overview

Problem

Vehicle seats designed for two users face challenges in maintaining the strength of attachment between the backrest and the seat frame, leading to potential separation during impacts, which compromises user safety and requires complex assembly processes.

Innovation Solution

A vehicle seat design featuring a common joint with a pivot axis and rib configuration that enhances the attachment strength between the backrest and the seat frame, allowing for secure sliding and rotation while preventing separation during impacts, and simplifies assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the rib is positioned at an angle between -20° and +20° relative to the vertical direction, then the assembly process is simplified, but the attachment strength deteriorates during impacts causing backrest separation

Engineering Contradiction:
Improveassembly processVSAvoidattachment strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the orientation angle parameter of the rib from the conventional -20° to +20° range to a new range of +30° to +60° relative to the vertical direction. This parameter modification simultaneously achieves both objectives: the angled configuration maintains assembly simplicity while the increased angle provides superior impact resistance and prevents backrest separation by optimizing the force distribution during collision events.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a common pivot axis is used for both backrests, then device complexity is reduced, but reliability deteriorates due to potential detachment during impacts

Engineering Contradiction:
Improvejoint structureVSAvoidattachment reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent modifies the geometric parameters of the common pivot axis system by specifying precise angular ranges for the rib orientation (+30° to +60°) and defining the spatial relationship between the pivot axis and backrest mounting points. These parameter changes enable the simplified common pivot structure to maintain both low complexity and high reliability by optimizing the mechanical advantage and force distribution during impact events.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates a design feature where the common pivot axis system is pre-configured with geometric parameters that inherently absorb and distribute impact forces. The specific angular configuration of the rib and pivot axis creates a mechanical cushioning effect that prevents sudden detachment during collisions, addressing reliability concerns before impacts occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If the housing and lateral portion are configured for sliding movement, then ease of operation is improved, but stability deteriorates during rearward impacts

Engineering Contradiction:
Improvebackrest adjustmentVSAvoidmounting stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent changes the geometric parameters of the sliding mechanism by defining the rib angle range (+30° to +60°) and the relative positioning of the housing and lateral portion. This parameter optimization allows the backrest to maintain smooth adjustability during normal operation while the angled rib configuration provides enhanced resistance to rearward impact forces, preventing excessive movement or detachment during collisions.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3944985B1Vehicle seat
Publication Date: 2024.10.30 FAURECIA SIEGES D AUTOMOBILE SA
  • EP3944985B1 patent drawingFigure 1
  • EP3944985B1 patent drawingFigure 2
  • EP3944985B1 patent drawingFigure 3

AI summary

A vehicle seat (1) configured to accommodate at least two users, comprising: - a seat frame (2), - a first backrest (3) and a second backrest (4) articulated and pivoting to the seat frame (2) about a transverse axis (Y1), via a common joint (5), comprising: -- a pivot axis (51) including a first lateral portion (51L), -- a first housing (52) formed on the first backrest (3) and internally receiving the first lateral portion (51L) while allowing rotation of the first backrest (3). The first lateral portion (51L) has a projecting rib (55) and the first housing (52) has a shape substantially resembling a keyhole, complementary to the radial section of the first lateral portion (51L). The rib (55) is oriented at an angle (A55) between 30° and 60° with respect to the vertical direction (Z) of the seat (1).