Turnover Mechanism for Vehicle Headrests

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Solution Overview

Problem

Current turnover headrest structures for vehicle seats are complex, costly, and lack reliable locking mechanisms under external forces, hindering improved ride comfort and safety for rear seat passengers.

Innovation Solution

A simple and cost-effective turnover mechanism featuring a bracket assembly with a cam, torsion spring, locking pawl piece, and tooth plate, which self-locks under external force, allowing for reliable operation and easy installation in headrest or backrest frameworks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a turnover headrest structure is implemented, then the field of view for rear seat passengers is improved, but the structure becomes complex and manufacturing cost increases

Engineering Contradiction:
Improvefield of viewVSAvoidstructure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The turnover mechanism is divided into independent functional modules: bracket assembly, cam mechanism, locking pawl piece, and resetting component. Each module performs a specific function and can be manufactured separately, simplifying the overall complex structure while maintaining the turnover functionality for improved field of view.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cam mechanism acts as an intermediary between the resetting component and the locking pawl piece. It converts the resetting force into the appropriate motion to engage or disengage the locking mechanism, enabling reliable turnover operation without requiring direct complex interaction between all components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a turnover headrest structure is implemented, then the field of view for rear seat passengers is improved, but manufacturing cost increases

Engineering Contradiction:
Improvefield of viewVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

By segmenting the mechanism into standardizable modules (bracket assembly, cam, locking pawl, torsion spring), each component can be manufactured using conventional processes and assembled, reducing overall manufacturing cost while achieving the turnover function for improved rear passenger visibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mechanism uses simple, inexpensive materials and components such as stamped metal brackets, standard torsion springs, and basic cam profiles, avoiding expensive materials or complex machining, thereby reducing manufacturing cost while maintaining functional reliability.

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

3Reliability

If existing locking mechanisms are used, then the headrest can be locked, but the locking is not reliable under external force

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

Solution Approach 1:

The locking mechanism is designed so that external forces applied to the headrest during turnover automatically strengthen the locking engagement. The cam and locking pawl geometry is such that load during the turnover process drives the pawl deeper into the cam groove, converting the potentially harmful external force into a beneficial locking action that prevents accidental disengagement.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The torsion spring in the resetting component is pre-loaded to provide sufficient resetting force before turnover occurs. This pre-loaded energy ensures that the locking mechanism can reliably overcome any external forces that might attempt to disengage the lock, maintaining reliability without adding complex active control systems.

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

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 mechanism provides a reliable, cost-effective, and easy-to-install solution for turning headrests or other fixed members, enhancing passenger comfort and safety by ensuring secure locking and easy operation.

Implementation Method 1

the cam resetting component is a cam resetting torsion spring, the cam resetting torsion spring is wound on the cam shaft, one end of the cam resetting torsion spring acts on the cam, and the other end acts on the second bracket wall

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Implementation Method 2

an outer surface of the unlocking drive arm is connected to the second locking step surface of the locking pawl through a first self-locking arc surface, the locking tooth plate is provided with a second self-locking arc surface, and the first self-locking arc surface on the locking pawl piece is coupled to the second self-locking arc surface on the locking tooth plate in a locked state to form self-locking

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3718819B1Turnover mechanism
Publication Date: 2023.04.19 YANFENG ADIENT SEATING CO LTD
  • EP3718819B1 patent drawingFigure 1~2
  • EP3718819B1 patent drawingFigure 3~4
  • EP3718819B1 patent drawingFigure 5

AI summary

A turnover mechanism is disclosed. The turnover mechanism includes a bracket assembly, a rotatable cam, a cam resetting component, a locking pawl piece, a rotating shaft, and a rotating shaft resetting torsion spring. The cam is axially disposed on the bracket assembly. The cam resetting component is connected to the cam and the bracket assembly. The locking pawl piece is axially disposed on the bracket assembly. The cam drives the locking pawl piece to move between a locked state and an unlocked state through forward and reverse movements. The rotating shaft is axially disposed on the bracket assembly and is provided with a locking tooth plate. When the locking pawl piece is in the locked state, a locking pawl in the locking pawl piece and a locking groove on the locking tooth plate are locked and engaged, and the rotating shaft and the bracket assembly are restricted from relative rotation by the locking tooth plate. When the locking pawl piece is at an unlocked position, the locking pawl in the locking pawl piece and the locking groove on the locking tooth plate are unlocked and disengaged, and the rotating shaft and the bracket assembly are rotatable relatively. The rotating shaft resetting torsion spring is connected to the locking tooth plate and the bracket assembly. The rotating shaft resetting torsion spring drives the locking tooth plate and the rotating shaft to rotate relative to the bracket assembly.