Head Restraint Linear Rotational Locking Mechanism

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Solution Overview

Problem

Existing head restraints require two hands to adjust due to the need for separate control activation and high effort to move, and often lack adjustable contours, leading to discomfort and increased noise and vibration.

Innovation Solution

A head restraint assembly with a linear and rotational locking mechanism using a shaft and slide, allowing continuous vertical and angular adjustments, supported by torsional springs and bushings, and a synchronization mechanism for synchronized lateral portion movement, reducing the need for user interface operation in forward angular adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a locking mechanism is used to reduce noise and vibration, then noise and vibration are reduced, but the effort required to move the head restraint increases

Engineering Contradiction:

Improvenoise and vibrationVSAvoideffort to move head restraint

Core Design Contradiction:

Object-affected harmful factorsVSForce

Solution Approach 1:

The head restraint system transitions from a static locked position to a dynamic adjustable state. The mechanism allows the head restraint to be easily moved between positions (dynamic adjustment) while maintaining stability when locked. The control mechanism enables temporary release of the locking force, allowing smooth movement without requiring excessive force to overcome static friction.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the friction parameter dynamically. In the locked state, high friction maintains stability and reduces noise/vibration. When the control is activated, the friction parameter is reduced to allow easy movement. This parameter change enables the system to provide both stability when needed and ease of adjustment when activated.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If a control mechanism is located away from the head restraint, then the locking mechanism can be simplified, but the ease of operation deteriorates

Engineering Contradiction:

Improvelocking mechanism complexityVSAvoidhead restraint adjustment convenience

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The control mechanism is merged with the head restraint structure itself. The control is integrated into the head restraint housing or frame, placing it within easy reach of the user's hand when adjusting the head restraint position. This integration eliminates the need for separate control locations and allows one-handed operation while maintaining a relatively simple locking mechanism.

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If high sliding friction is used to reduce noise and vibration, then noise and vibration are minimized, but the effort to activate the control and move the head restraint increases

Engineering Contradiction:

Improvebuzz, squeak, rattleVSAvoidcontrol activation and head restraint movement

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The system uses periodic or intermittent control activation rather than continuous high friction. The control mechanism is activated temporarily during adjustment, providing low friction for movement. Once adjustment is complete, the locking mechanism re-engages to provide high friction for noise and vibration reduction. This periodic switching between low and high friction states optimizes both ease of operation and noise reduction.

Inventive Principle:

Principle #19Periodic action

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

Enables comfortable, one-handed adjustment of head restraints with reduced effort and noise, providing infinite positional adjustment and improved user convenience while minimizing noise and vibration.

Implementation Method 1

supported by torsional springs and bushings

Methodology Applied

Scientific EffectTorsional springs: Torsion Spring

Implementation Method 2

supported by torsional springs and bushings

Methodology Applied

Scientific EffectBushing: Friction

Data Source

PatentEP3523159B1Infinite adjustment mechanism for a head restraint

Publication Date: 2021.06.16 ADIENT LUXEMBOURG HLDG SARL

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AI summary

A head restraint for a seat being adjustable in a vertical direction, and angularly adjustable with regard to lateral portions of the head restraint. A mechanism providing this adjustability is a linear and rotational locking mechanism with a shaft and a slide. The slide is selectively slidably and rotatably mounted on the shaft. The slide has a locked state which linearly and rotationally fixes the slide on, and with respect to, the shaft. The slide has a release state where the slide is linearly and rotatably movable on the shaft. The slide is fixable in a plurality of linear and rotational positions on the shaft in the locked state. The number of linear and rotational positions on the shaft is considered infinite since for all practical purposes, the slide is not restricted to individual discrete positions, but is continuously adjustable to practically any linear and rotational position.