Vehicle Backrest Automatic Unlocking Mechanism for Middle Seat Safety

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Solution Overview

Problem

The existing backrest construction of vehicle rear seats lacks a secure locking mechanism for the middle rear seat backrest, leading to safety concerns when the outer seat backrest is folded down, as the belt retractor for the middle rear seat is not used safely due to the unlocked and unlockable backrest part.

Innovation Solution

An automatic unlocking device is activated when the outer seat backrest is pivoted from its driving position to a folded-down position, allowing the backrest part to be swiveled and unlocked independently, with a driver plate and lever element mechanism that enables easy activation, utilizing a recliner element and cam design for smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the outer seat backrest is folded down to increase cargo space, then the cargo area is expanded, but the backrest part becomes unlocked and unsafe for middle rear seat passengers

Engineering Contradiction:
Improvecargo spaceVSAvoidpassenger safety
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The backrest is divided into an outer seat backrest and an inner backrest part that can be independently controlled. The outer backrest can be folded down for cargo space while the inner backrest part remains locked and safe for middle seat passengers, separating the cargo access function from the passenger safety function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The unlocking device is automatically activated when the outer seat backrest is pivoted from the driving position toward the folded-down position. This preliminary unlocking action ensures that the backrest part can be independently secured before passengers attempt to use the middle seat, preventing the safety hazard that would otherwise occur.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the backrest part is locked to ensure passenger safety, then safety is improved, but the device complexity increases with additional locking mechanisms

Engineering Contradiction:
Improvepassenger safetyVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The unlocking device combines multiple functions into a single mechanism: it detects the outer backrest position, automatically unlocks the backrest part, and allows independent folding. This integration achieves enhanced safety without proportionally increasing complexity, as one actuation system performs multiple safety-related functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses the motion of the outer seat backrest itself to trigger the unlocking mechanism through the driver plate and lever element. The system serves itself by using its own operational movement to activate the safety feature, eliminating the need for separate sensors, motors, or control systems that would increase complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If the backrest part can be independently unlocked to improve safety, then passenger safety is enhanced, but the ease of operation decreases due to automatic activation requirements

Engineering Contradiction:
Improvepassenger safetyVSAvoidbackrest operation simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The unlocking mechanism automatically activates itself through the driver plate that is struck by the outer seat backrest during its normal folding motion. The system uses its own operational movement to trigger the safety feature, eliminating the need for separate sensors, motors, or control systems that would complicate the operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The unlocking device is automatically activated when the outer seat backrest is pivoted from the driving position toward the folded-down position. This preliminary unlocking action ensures that the backrest part can be independently secured before passengers attempt to use the middle seat, preventing the safety hazard that would otherwise occur.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If a simple lever element mechanism is used to activate the unlocking device, then manufacturing cost is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvemanufacturing costVSAvoidlever element alignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The mechanism uses simple, inexpensive components like a driver plate, lever element, and cam instead of complex electronic sensors, motors, or control systems. These basic mechanical parts are inexpensive to manufacture and replace, reducing overall system cost even though they require precise assembly.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The backrest is divided into an outer seat backrest and an inner backrest part that can be independently controlled. The outer backrest can be folded down for cargo space while the inner backrest part remains locked and safe for middle seat passengers, separating the cargo access function from the passenger safety function.

Inventive Principle:
Principle #1Segmentation

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

Ensures the backrest part can be safely and easily unlocked and pivoted to a folded-down position, enhancing passenger safety by allowing secure use of the safety belt for the middle rear seat, while maintaining a space-saving and cost-effective design.

Implementation Method 1

the recliner element and is durable, which can be pivoted upwards with continued pivoting movement of the outer seat backrest in the direction of its folded-down position

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP3254891B1Backrest structure
Publication Date: 2019.04.10 ADIENT LUXEMBOURG HLDG SARL
  • EP3254891B1 patent drawingFigure 1~2
  • EP3254891B1 patent drawingFigure 3~4

AI summary

The invention relates to a backrest construction (1) of a rear seat of a vehicle, wherein the backrest construction (1) comprises an outer seat backrest (2) with a first locking construction for locking the outer seat backrest (2) in a driving position and a backrest part (3) with a second locking construction for locking the backrest part (3) in a driving position, characterized by a release device for unlocking the backrest part (3) from its driving position, wherein the release device can be automatically activated by pivoting the outer seat backrest (2) from its driving position in the direction of its folded-down position.