Rear Seat Backrest Locking Ring for Shock-Resistant Pivoting

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Solution Overview

Problem

Existing vehicle rear bench systems lack effective locking mechanisms to prevent unlocking during shocks, especially when loaded with luggage, which can compromise safety.

Innovation Solution

A locking system comprising a war-shaped end on a first locking element and a complementary locking ring on a second element, ensuring secure engagement and resistance to shocks, with a recall spring to maintain the locking position and allow easy unlocking for conversion between file and armrest modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a simple pivot mechanism is used for the backrest portion, then ease of operation is improved, but reliability deteriorates due to inability to prevent unlocking during impacts

Engineering Contradiction:
Improveease of pivotingVSAvoidlocking stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking elements are pre-positioned and automatically engage when the backrest portion is rotated to the upright position, preventing unlocking before an impact can occur. The ogive-shaped end and complementary locking element are designed to automatically lock without requiring additional user action.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The ogive-shaped end of the first locking element provides a curved, domed surface that complements the second locking element, creating a mechanically interlocking joint that resists separation forces during impacts while maintaining smooth rotational movement during operation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If a robust locking mechanism is implemented to prevent unlocking during impacts, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvelocking stabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking function is integrated directly into the pivot mechanism itself, combining the rotational support and locking functions into a single unified system. The locking elements are incorporated as part of the pivot assembly rather than as separate, additional components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking mechanism automatically engages and disengages based on the position and movement of the backrest portion itself, without requiring external control systems, sensors, or additional actuation mechanisms. The geometry of the locking elements causes automatic engagement when the backrest is upright and automatic disengagement when tilted.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If the locking mechanism uses simple geometric shapes, then ease of manufacture is improved, but manufacturing precision requirements worsen due to the ogive-shaped end

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidogive shape precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The ogive shape parameters (curvature radius, length, profile) are optimized to provide sufficient locking engagement while remaining compatible with standard manufacturing tolerances. The geometry is designed so that even with normal manufacturing variations, the locking function remains effective.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4497628A1Rear seat back element for a vehicle
Publication Date: 2025.01.29 FAURECIA SIEGES D AUTOMOBILE SA
  • EP4497628A1 patent drawingFigure 1
  • EP4497628A1 patent drawingFigure 2
  • EP4497628A1 patent drawingFigure 3~4

AI summary

A rear vehicle seat backrest (1) comprising: - a backrest portion (2) also serving as an armrest, capable of pivoting about a pivot axis (P) between a raised position to form a backrest and a lowered position to form an armrest, - a backrest frame (6) intended to be covered by said backrest portion (2) in the raised position, - a first locking element (8) fixed to one of the backrest frame (6) and the backrest portion (2) and having a rod (9) and an ogive-shaped end (10), - a second locking element (11) fixed to the other of the backrest frame (6) and the backrest portion (2) and having a locking ring (12), - the ogive-shaped end (10) of the first locking element (8) being configured to cooperate with the locking ring (12) of the second locking element (11) so as to allow the backrest portion (2) in the raised position to be locked to the frame of file (6).